Transistor radio parts

Transistor radio parts DEFAULT

Transistor radio

Portable radio receiver

This article is about an electronic device. For the fourth studio album by M. Ward, see Transistor Radio (album).

A classic Emersontransistor radio, circa 1958

A transistor radio is a small portable radio receiver that uses transistor-based circuitry. Following the invention of the transistor in 1947—which revolutionized the field of consumer electronics by introducing small but powerful, convenient hand-held devices—the Regency TR-1 was released in 1954 becoming the first commercial transistor radio. The mass-market success of the smaller and cheaper Sony TR-63, released in 1957, led to the transistor radio becoming the most popular electronic communication device of the 1960s and 1970s. Transistor radios are still commonly used as car radios. Billions of transistor radios are estimated to have been sold worldwide between the 1950s and 2012.[citation needed]

The pocket size of transistor radios sparked a change in popular music listening habits, allowing people to listen to music anywhere they went. Beginning around 1980, however, cheap AM transistor radios were superseded initially by the boombox and the Sony Walkman, and later on by digitally-based devices with higher audio quality such as portable CD players, personal audio players, MP3 players and (eventually) by smartphones, many of which contain FM radios.[1][2]


A seven-transistor USSR radio Orljonok with the back open, showing parts.

Before the transistor was invented, radios used vacuum tubes. Although portable vacuum tube radios were produced, they were typically bulky and heavy. The need for a low voltage high current source to power the filaments of the tubes and high voltage for the anode potential typically required two batteries. Vacuum tubes were also inefficient and fragile compared to transistors and had a limited lifetime.

Bell Laboratories demonstrated the first transistor on December 23, 1947.[3] The scientific team at Bell Laboratories responsible for the solid-state amplifier included William Shockley, Walter Houser Brattain, and John Bardeen.[4] After obtaining patent protection, the company held a news conference on June 30, 1948, at which a prototype transistor radio was demonstrated.[5]

There are many claimants to the title of the first company to produce practical transistor radios, often incorrectly attributed to Sony (originally Tokyo Telecommunications Engineering Corporation). Texas Instruments had demonstrated all-transistor AM (amplitude modulation) radios as early as May 25, 1954,[6][7] but their performance was well below that of equivalent vacuum tube models. A workable all-transistor radio was demonstrated in August 1953 at the Düsseldorf Radio Fair by the German firm Intermetall.[8] It was built with four of Intermetall's hand-made transistors, based upon the 1948 invention of the "Transistor"-germanium point-contact transistor by Herbert Mataré and Heinrich Welker. However, as with the early Texas Instruments units (and others) only prototypes were ever built; it was never put into commercial production. RCA had demonstrated a prototype transistor radio as early as 1952, and it is likely that they and the other radio makers were planning transistor radios of their own, but Texas Instruments and Regency Division of I.D.E.A., were the first to offer a production model starting in October 1954.[9]

Sanyo8S-P3 transistor radio, which received AM and shortwave bands.

The use of transistors instead of vacuum tubes as the amplifier elements meant that the device was much smaller, required far less power to operate than a tube radio, and was more resistant to physical shock. Since the transistor's base element draws current, its input impedance is low in contrast to the high input impedance of the vacuum tubes.[10] It also allowed "instant-on" operation, since there were no filaments to heat up. The typical portable tube radio of the fifties was about the size and weight of a lunchbox and contained several heavy, non-rechargeable batteries — one or more so-called "A" batteries to heat the tube filaments and a large 45- to 90-volt "B" battery to power the signal circuits. By comparison, the transistor radio could fit in a pocket and weighed half a pound or less, and was powered by standard flashlight batteries or a single compact 9-volt battery. The 9-volt battery was introduced for powering transistor radios.[citation needed]

Early commercial transistor radios[edit]

Regency TR-1[edit]

Two companies working together, Texas Instruments of Dallas, and Industrial Development Engineering Associates (I.D.E.A.) of Indianapolis, Indiana, were behind the unveiling of the Regency TR-1, the world's first commercially produced transistor radio. Previously, Texas Instruments was producing instrumentation for the oil industry and locating devices for the U.S. Navy and I.D.E.A. built home television antenna boosters. The two companies worked together on the TR-1, looking to grow revenues for their respective companies by breaking into this new product area.[5] In May 1954, Texas Instruments had designed and built a prototype and was looking for an established radio manufacturer to develop and market a radio using their transistors. (The Chief Project Engineer for the radio design at Texas Instruments' headquarters in Dallas, Texas was Paul D. Davis, Jr., who had a degree in Electrical Engineering from Southern Methodist University. He was assigned the project due to his experience with radio engineering in World War II.) None of the major radio makers including RCA, GE, Philco, and Emerson were interested. The President of I.D.E.A. at the time, Ed Tudor, jumped at the opportunity to manufacture the TR-1, predicting sales of the transistor radios at "20 million radios in three years".[11] The Regency TR-1 was announced on October 18, 1954, by the Regency Division of I.D.E.A., was put on sale in November 1954 and was the first practical transistor radio made in any significant numbers.[12]Billboard reported in 1954 that "the radio has only four transistors. One acts as a combination mixer-oscillator, one as an audio amplifier, and two as intermediate-frequency amplifiers."[13] One year after the release of the TR-1 sales approached the 100,000 mark. The look and size of the TR-1 was well received, but the reviews of the TR-1's performance were typically adverse.[11] The Regency TR-1 is patented by Richard C. Koch, US 2892931 , former Project Engineer of I.D.E.A.

Raytheon 8-TP-1[edit]

In February 1955, the second transistor radio, the 8-TP-1, was introduced by Raytheon. It was a larger portable transistor radio, including an expansive four-inch speaker and four additional transistors (the TR-1 used only four). As a result, the sound quality was much better than the TR-1. An additional benefit of the 8-TP-1 was its efficient battery consumption. In July 1955, the first positive review of a transistor radio appeared in the Consumer Reports that said, "The transistors in this set have not been used in an effort to build the smallest radio on the market, and good performance has not been sacrificed." Following the success of the 8-TP-1, Zenith, RCA, DeWald, and Crosley began flooding the market with additional transistor radio models.[11]

Chrysler Mopar 914HR[edit]

1955 Chrysler – Philco all transistor car radio – "Breaking News" radio broadcast announcement.

Chrysler and Philco announced that they had developed and produced the world's first all-transistor car radio in the April 28th 1955 edition of the Wall Street Journal.[14] Chrysler made the all-transistor car radio, Mopar model 914HR, available as an "option" in fall 1955 for its new line of 1956 Chrysler and Imperial cars, which hit the showroom floor on October 21, 1955. The all-transistor car radio was a $150 option (equivalent to $1,450 in 2020).[15][16][17][18]

Japanese transistor radios[edit]

The circuit of a Japanese 5 transistor radio.

While on a trip to the United States in 1952, Masaru Ibuka, founder of Tokyo Telecommunications Engineering Corporation (now Sony), discovered that AT&T was about to make licensing available for the transistor. Ibuka and his partner, physicist Akio Morita, convinced the Japanese Ministry of International Trade and Industry (MITI) to finance the $25,000 licensing fee (equivalent to $243,640 today).[19] For several months Ibuka traveled around the United States borrowing ideas from the American transistor manufacturers. Improving upon the ideas, Tokyo Telecommunications Engineering Corporation made its first functional transistor radio in 1954.[11] Within five years, Tokyo Telecommunications Engineering Corporation grew from seven employees to approximately five hundred.[citation needed]

Other Japanese companies soon followed their entry into the American market and the grand total of electronic products exported from Japan in 1958 increased 2.5 times in comparison to 1957.[20]

Sony TR-55[edit]

In August 1955, while still a small company, Tokyo Telecommunications Engineering Corporation introduced their TR-55 five-transistor radio under the new brand name Sony.[21][22] With this radio, Sony became the first company to manufacture the transistors and other components they used to construct the radio. The TR-55 was also the first transistor radio to utilize all miniature components. It is estimated that only 5,000 to 10,000 units were produced.[citation needed]

Sony TR-63[edit]

The TR-63 was introduced by Sony to the United States in December 1957. The TR-63 was 6 mm (1⁄4 in) narrower and 13 mm (1⁄2 in) shorter than the original Regency TR-1. Like the TR-1 it was offered in four colors: lemon, green, red, and black. In addition to its smaller size, the TR-63 had a small tuning capacitor and required a new battery design to produce the proper voltage. It used the nine-volt battery, which would become the standard for transistor radios. Approximately 100,000 units of the TR-63 were imported in 1957.[11] This "pocketable" (the term "pocketable" was a matter of some interpretation, as Sony allegedly had special shirts made with oversized pockets for their salesmen) model proved highly successful.[23]

The TR-63 was the first transistor radio to sell in the millions, leading to the mass-market penetration of transistor radios.[24] The TR-63 went on to sell seven million units worldwide by the mid-1960s.[25] With the visible success of the TR-63, Japanese competitors such as Toshiba and Sharp Corporation joined the market. By 1959, in the United States market, there were more than six million transistor radio sets produced by Japanese companies that represented $62 million in revenue.[11]

The success of transistor radios led to transistors replacing vacuum tubes as the dominant electronic technology in the late 1950s.[26] The transistor radio went on to become the most popular electronic communication device of the 1960s and 1970s. Billions of transistor radios are estimated to have been sold worldwide between the 1950s and 2012.[24]


Prior to the Regency TR-1, transistors were difficult to produce. Only one in five transistors that were produced worked as expected (only a 20% yield) and as a result the price remained extremely high.[11] When it was released in 1954, the Regency TR-1 cost $49.95 (equivalent to $482 today) and sold about 150,000 units. Raytheon and Zenith Electronics transistor radios soon followed and were priced even higher. In 1955, Raytheon's 8-TR-1 was priced at $80 (equivalent to $773 today).[11] By November 1956 a transistor radio small enough to wear on the wrist and a claimed battery life of 100 hours cost $29.95.[27]

Sony's TR-63, released in December 1957, cost $39.95 (equivalent to $369 today).[11] Following the success of the TR-63 Sony continued to make their transistor radios smaller. Because of the extremely low labor costs in Japan, Japanese transistor radios began selling for as low as $25.[11] By 1962, the TR-63 cost as low as $15 (equivalent to $128 today),[24] which led to American manufacturers dropping prices of transistor radios down to $15 as well.[11]

In popular culture[edit]

An early 2000s transistor radio (Sony Walkman SRF-S84 transistor radio, released 2001, shown without earphones)

Transistor radios were extremely successful because of three social forces — a large number of young people due to the post–World War II baby boom, a public with disposable income amidst a period of prosperity, and the growing popularity of rock 'n' roll music. The influence of the transistor radio during this period is shown by its appearance in popular films, songs, and books of the time, such as the movie Lolita.

In the late 1950s, transistor radios took on more elaborate designs as a result of heated competition. Eventually, transistor radios doubled as novelty items. The small components of transistor radios that became smaller over time were used to make anything from "Jimmy Carter Peanut-shaped" radios to "Gun-shaped" radios to "Mork from Ork Eggship-shaped" radios. Corporations used transistor radios to advertise their business. "Charlie the Tuna-shaped" radios could be purchased from Star-Kist for an insignificant amount of money giving their company visibility amongst the public. These novelty radios are now bought and sold as collectors' items amongst modern-day collectors.[28][29][30]

Rise of portable audio players[edit]

Since the 1980s, the popularity of radio-only portable devices declined with the rise of portable audio players which allowed users to carry and listen to tape recorded music of their choosing and may additively came with a radio tuner. This began in the late 1970s with boom boxes and portable cassette players such as the Sony Walkman, followed by portable CD players. A common type now is the portable digital audio player. This type of device is a popular choice with listeners who are dissatisfied with terrestrial music radio because of a limited selection of music and reception problems. However, transistor radios are still popular for news, talk radio, weather, live sporting events, and emergency alert applications.[citation needed]

See also[edit]


  1. ^Petraglia, Dave (5 March 2014). "Why You Owe Your Smartphone To The Transistor Radio". Thought Catalog.
  2. ^Bray, Hiawatha (6 November 2014). "Is Your Smartphone Ready for Radio?". The Boston Globe.
  3. ^Arns, R.G. (October 1998). "The other transistor: early history of the metal–oxide–semiconductor field-effect transistor"(PDF). Engineering Science and Education Journal. 7 (5): 233–240. doi:10.1049/esej:19980509. Retrieved 13 April 2021.
  4. ^Handy et al. (1993), p. 13.
  5. ^ ab"The Revolution in Your Pocket". Archived from the original on 20 August 2006. Retrieved 20 April 2010.
  6. ^Invention and Technology Magazine, Fall 2004, Volume 20 Issue 2, "The Revolution in your Pocket", Author: Robert J. Simcoe
  7. ^Book Title: TI, the Transistor, and Me, Author: Ed Millis, page 34
  8. ^Article: "The French Transistor", Author: Armand Van Dormael, page 15, Source: IEEE Global History Network
  9. ^website:, Regency TR-1 Transistor Radio History
  10. ^Donald L. Stoner & L.A. Earnshaw (1963). The Transistor Radio Handbook: Theory, Circuitry, and Equipment. Editors and Engineers, Ltd. page 32
  11. ^ abcdefghijkDavid Lane & Robert Lane (1994). Transistor Radios: A Collector's Encyclopedia and Price Guide. Wallace-Homestead Book Company. pp. 2–7. ISBN .
  12. ^Deffree, Suzanne (17 October 2017). "TI announces 1st transistor radio, October 18, 1954". EDN. Retrieved 16 October 2018.
  13. ^"Regency markets pocket transistor radio". Billboard. 30 October 1954.
  14. ^Wall Street Journal, "Chrysler Promises Car Radio With Transistors Instead of Tubes in '56", April 28th 1955, page 1
  15. ^Hirsh, Rick. "Philco's All-Transistor Mopar Car Radio". Retrieved 18 February 2015.
  16. ^"Mopar 914-HR Ch= C-5690HR Car Radio Philco, Philadelphia".
  17. ^"North America | FCA Group".
  18. ^Chrysler Imperial Owners Manual, 1956, Page 13
  19. ^"Sony History. Chapter4: Ibuka's First Visit to the United States". Sony. Retrieved 16 September 2017.
  20. ^Handy et al. (1993), pp. 23–29.
  21. ^John Nathan (1999). SONY : the private life. Houghton Mifflin Company. ISBN . page 35
  22. ^"Transistor Radios". ScienCentral. 1999. Retrieved 19 January 2010.
  23. ^"Sony Global – Sony History". Archived from the original on 20 August 2008. Retrieved 1 September 2008.
  24. ^ abcSkrabec, Quentin R., Jr. (2012). The 100 Most Significant Events in American Business: An Encyclopedia. ABC-CLIO. pp. 195–7. ISBN .
  25. ^Snook, Chris J. (29 November 2017). "The 7 Step Formula Sony Used to Get Back On Top After a Lost Decade". Inc.
  26. ^Kozinsky, Sieva (8 January 2014). "Education and the Innovator's Dilemma". Wired. Retrieved 14 October 2019.
  27. ^"Broadcast Band – All Transistor Wrist Radio". Galaxy (advertisement). November 1956. p. 1. Retrieved 18 December 2013.
  28. ^Handy et al. (1993), pp. 46–51.
  29. ^"N.A.". Antique Radio Classified. John V. Terrey. June 2002. p. 10.
  30. ^"N.A.". Antique Radio Classified. John V. Terrey. March 2008. p. 6.
  • Handy; Erbe; Blackham; Antonier (1993). Made in Japan: Transistor Radios of the 1950s and 1960s. Chronicle Books. ISBN .

Further reading[edit]

  • Michael F. Wolff: "The secret six-month project. Why Texas Instruments decided to put the first transistor radio on the market by Christmas 1954 and how it was accomplished." IEEE Spectrum, December 1985, pages 64–69
  • Transistor Radios: 1954–1968 (Schiffer Book for Collectors) by Norman R. Smith
  • Unique books on Transistor Radios by Eric Wrobbel
  • The Portable Radio in American Life by University of Arizona professor Michael Brian Schiffer, Ph.D. (The University of Arizona Press, 1991).
  • Restoring Pocket Radios (DVD) by Ron Mansfield and Eric Wrobbel. (, 2002).
  • The Regency TR-1 story, based on an interview with Regency co-founder, John Pies (partner with Joe Weaver) "Regency's Development of the TR-1 Transistor Radio" website
  • Bryant & Cones (1995). The Zenith Transoceanic The Royalty of Radios. Schiffer Book for Collectors. Schiffer. pp. 110–120. ISBN .

External links[edit]


Re: Transistor radio parts

Postby Dean Huster » Mar Tue 04, 2014 6:28 am

I found it George. This list is darned near 14 years old now. If I had to do it over using the magazines available, I would have nearly the number of vendors that I do. Understand that a lot of these companies may be long out of business; addresses and phone numbers may have changed; URLs may be no good anymore. Just roll with the punches and do a bit of research on names that don't work well. My apologies if this takes up too much forum space. If it's inappropriate, just delete it. Here it is:

Parts Resources
Compiled by Dean Huster

This is a condensed list compiled from all of the catalogs that I had on hand somewhere around the year 2001 or 2002. It serves as a quick guide for finding elusive parts since many of these oddities are noted as described in the next paragraph. Note that the items offered will change from catalog edition to catalog edition, so the list will be dated and has not been updated after 2001. Companies that carry "surplus" material will change more often than the "regular" suppliers. Some of the catalogs may have been from 1997. Dates in parenthesis after the company name indicate the newest catalog used. If nothing else, this list provides company name, e-mail addresses, s-mail addresses, voice phone numbers and FAX phone numbers. Some of these companies may no longer exist. At least it's a resource that may be handy for you, especially if you're new to electronics or are searching for oddball or obsolete items.

This list was originally written on WordPerfect 8.0 and I've spent a lot of time and patience converting it over to be InfoPop compatible so that all of the italics and bold face type comes through. At least give me credit for that. I may have goofed up somewhere. Oops. Too bad.

Items in the product listings that are in bold italics are an especially good selection of parts from that vendor or are parts that are hard to find. This information is taken from the vendors' paper catalogs and some information may be somewhat dated.

MAT Electronics, Inc. (2001)
400 Pike Road
Huntingdon Valley PA 19006-1610
800-628-1118 (voice)
800-628-1005 (fax)
[email protected]

Surveillance and security equipment; TV flybacks; original replacement semiconductors (STK, LA, TDA, 2SB, etc.), NTE replacement semiconductors; VCR parts and tools; 1/4-w & ½-w 5% resistors; power resistors; SMT resistors and capacitors; electrolytic capacitors; TV antennas; cable TV and DSS supplies; cable; crimp terminals; adaptors; connectors; prefab cables; telephone accessories; cordless phone batteries; TV/monitor wall mounts; video game accessories/tools; remotes; turntable styli; auto audio; speakers; PA equipment; generic batteries; camcorder batteries; chemicals; computer connectors, wall plates, accessories; soldering equipment ( Weller, Hakko, Wahl); tools (Xcelite, Panavise); bench lighting; ticket books; training videos; service software; alignment media (VHS, 8mm, cassette, DVD); microwave oven parts; test equipment (B&K, LG Precision, Pomona).

Solid State, Inc., Tech Division (Nice stuff here!)
46 Farrand Street
Bloomfield N 07003
888-287-5487 (voice)
973-429-7150 (fax)

Test equipment (some weird stuff like non-contact thermometer, insulation tester, CO meter, refrigerant leak detector, clamp meters, spectrum analyzers, field strength analyzer, HV probe, differential probe, scope probes, premade cables; Triplett, Global Specialties, Protek, LG Precision); Mueller connectors; perf board; wire wrapping; PC etching; soldering equipment (Edsyn, Weller); solder & flux; educational kits (soldering, fiber optics); tools (Panavise, tackle boxes, service kits, trimpot tweaker, Xcelite, crimpers, spring hooks, bending jigs); storage boxes; parts cabinets; NTE replacement semiconductors; 74xx, 74LSxx, 74HCxx, 4xxx ICs; transistors (2Nxxx, IRFxxx, Vnxxx); thyristors; diodes (zener, Schottky, varactor); optocouplers; LEDs, fiber optic emitters & detectors; fiber optic cable (spools); capacitors (ceramic, mylar, monolythic, tantalum, variable, 160v electrolytic, electrolytic); RF chokes; audio & power transformers; potentiometers; resistors; crystals; oscillators; thermistors; wire & cable; fuses; heat shrink; calculators; computers & accessories.

All Electronics Corp. (2001)
(not to be confused with Alltronics)
POB 567
Van Nuys CA 91408-0567
800-826-5432 (voice)
818-781-2653 (fax)

Surplus outlet, merchandise changes periodically. LEDs (flashing, bicolor, IR, white, blue, mounting, bargraph); LCDs; lamps; lamp sockets; Cold Cathode Fluorescent lamps; switches (toggle, slide, rotary, push, mercury, hall effect, key, reed, pressure, vacuum); proximity sensors; rotary encoders; thermal switches; rechargeable batteries; battery holders; buzzers & noisemakers; wiring looms; small speakers; screw terminal blocks; microphones; crimp terminals; metal spacers & standoffs; cable ties; roller chain & sprockets; gears; motors; relays; solenoids; heat shrink; thermistors; fans; wire and cable; cameras; telephone jacks; connectors; adaptors; 0.1" headers; IDC connectors; premade cables; panel meters; DPMs; line cords; RFI filters; strain reliefs; GFCI outlet ($6.50 ea); photocell controllers; magnets; wall warts; transformers; "variacs"; knobs; pots; rubber feet; wheels; handles; capacitors ( photoflash, electrolytic, large mylar, HV mylar, mica); resistors; fuses; fuse holders; enclosures; perf board; PC board; ferric chloride; Press-n-Peel; Tinnit; tools; adhesives; linear integrated circuits; transistors; diodes (diacs, schottky, 40A rectifiers; HV rectifiers); heat sinks; books; little kits; inductors; torroids; power supplies; Parallax Stamp supplies.

Marlin P. Jones & Associates, Inc. (1997)
POB 12685
Lake Park FL 33403-0685
800-652-6733 (voice)
800-432-9937 (fax)
Orders: [email protected]
Technical information: [email protected]
Catalog requests: [email protected]

Surplus outlet, merchandise changes periodically. Security components; computer software instructional videos; power supplies; wall warts; transformers; fans; switches; telephone accessories; relays; motors; solenoids; pneumatic components; small kits; TV accessories; knobs; magnets; audio accessories; speakers (especially paging horns); buzzers & noisemakers; microphones; enclosures; rubber feet; lacing cord; panel meters; test equipment; prototyping boards; breadboarding accessories; tools ( carbide drill bits, diamond scribe, files, pliers, crimpers); chemicals; lamps; power resistors; potentiometers; capacitors ( super caps, trimmers, monolytyic, ceramic); displays; rectifiers; semiconductors; Peltier modules; LEDs, oscillators; connectors (UHF, N, BNC, IDC, mini DIN, 1/4", 3.5mm, RCA, DB); adaptors; crimp terminals; fuses; fuse holders; books; heat sinks; mirrors; laser diodes; computer accessories; power cords; ribbon cable; lenses; thermocouple wire; wire and cable; Parallax Stamp accessories; X-10 home automation.

Electronix Express, a Division of RSR Electronics, Inc.
365 Blair Road
Avenel NJ 07001
800-972-2225 (voice)
732-381-1006 (fax)
[email protected]

Tends to supply schools as a specialty area. Test equipment (Wavetek, B&K, Fluke, Simpson, Global Specialties); meter movements; trainers (digital, analog, µP, telecommunications, PC interface, PLDs); chip programmers; breadboards; prototyping boards; surfboards; antistatic foam, bags, labels, mats and accessories; wire-wrapping equipment; tools (Panavise, Xcelite, vernier calipers, micrometers, drills & bits); PCB etching ( Press-n-Peel – fantastic inventory and price!, Tinnit, ferric chloride, Kepro shear, tanks, screen printing); PCB material; test leads; storage boxes and cabinets; workbenches; carts; soldering equipment ( Ungar, Weller, Xytronic); relay racks & cabinets; integrated circuits (74xx, 74LSxx, 4xxx, ADC, DAC, UART, linear, 74HCxx, 6500, 6800, 8000, EPROM); IC sockets; diodes (rectifier, bridge, zener, fast recovery, Ge, varactor); transistors; thyristors[/i][/b]; EXR replacement semiconductors; calculators; crystals; oscillators; LEDs (blue, displays, bargraph, optocouplers); incandescent lamps; xenon tubes; fiber optics; HeNe laser; solar cells; switches; resistors; pots; capacitors ( NP electrolytic, mica, tantalum, trimmers, ceramic, monolythic, 160v, electrolytic); fixed inductors; variable inductors; ceramic filters; transformers; speakers; microphones; buzzers; connectors; perf boards; terminal strips (solder lug); crimp terminals; cables; fuses; fuse holders; knobs; cable clamps; hardware; batteries; wire and cable; heat shrink; coaxial cable; wire wrap; chemicals; books; video training tapes & CDs; circuit simulator software; computer accessories; degaussing coil; security systems; small kits.

Chaney Electronics, Inc.
POB 4116
Scottsdale AZ 85261
800-227-7312 (voice)
480-451-9495 (fax)

Lots and lots of small kits. Computer-based training; training kits; solar cells – interesting reading on the subject; PCB boards.

Brigar Electronics
7-9 Alice St.
Binghamton NY 13904
607-723-3111 (voice)
607-723-5202 (fax)
[email protected]

Surplus electronics dwelling a lot in industrial control. Motors (BIG servo motors); transformers; fans; power supplies; linear motion rolling guides; ball screws; pneumatic cylinders, regulators & valves; rotary encoders; stepper motors; ac oil capacitors; ribbon cable; huge variety of hook-up wire and cable.

Electronic School Supply
3070 Skyway Dr., Suite 303
Santa Maria CA 93455
800-726-0084 (voice)
805-928-0253 (fax)
[email protected]

Educational trainers (PLC, µP, fiber optics, digital, analog); tool kits; test equipment (Elenco, global Specialties); small kits; fiber optics accessories; breadboards; tools; integrated circuits (4xxx, 74xx, 74LSxx, linear, CA3xxx, Xrxxx, ADC, DAC, PAL, GAL, Z80-, 6xxx, 8xxx, memory chips, diodes, transistors, zeners, LEDs – good mfr. xref for memory); incandescent lamps, capacitors (electrolytic, mica, tantalum, film); resistors ( 1%, 5% and networks); inductors; trimpots; panel-mount pots; IC sockets; wire wrap; connectors; telephone/network cabling supplies & patch panels; switches; transformers.

Parts Express
725 Pleasant Valley Drive
Springboro OH 45066-1158
[email protected]

Home theater; remote controls; TV antennas; DSS equipment; MATV equipment; TV accessories; camcorder batteries; X-10; security; video game accessories; computer accessories; Category 5 cable & connectors; cordless & cellular phone batteries, antennas & accessories; telephone installation; belts; NTE replacement semiconductors (good selection); OEM semiconductors; capacitors (electrolytic, film, ceramic, large film, non-polarized electrolytics); resistors (film, power & dummy loads); switches; lamps; fuses; connectors; adaptors; heat shrink; crimp terminals; chemicals; cable ties; "E" clips; Ziplock bags; rubber feet; hardware; tools; Mag-Lite; storage bins; soldering supplies; test equipment (Triplett, Goldstar); wall warts; batteries (button cells, computer NiCd, lithium, gel cell, NiCd, 2-way radio); instructional videos; books; PCB etching supplies; breadboards; enclosures; small kits; Hammond transformers; vacuum tubes; tube sockets; chassis; vacuum tube amplifiers; wire & cable (snake, microphone, guitar, "Monster", flat under-rug, Cat 3, Cat 5, hook-up wire, high-current); CD supplies; test cables; headphones; loudspeaker building components (this is probably the biggest selection of this stuff anywhere on the market!); PA amplifiers; sound absorbing material; professional audio equipment; microphones; mic stands; cases; relay racks; turntable cartridges and styli; disco supplies; alarms; automotive (accessories, audio, amps, antennas, speakers, video, fusing, wiring, foam, liner, mats, speaker boxes, capacitors -- this is another big area of theirs).

280 Adams Blvd.
Farmingdale NY 11735
631-756-1750 (voice)
631-756-1763 (fax)

Unfortunately, these clowns seem to sell only to schools which is a real bummer since they have some very desirable inventory for hobbyists that may not be found elsewhere. I don't know for sure that they won't sell to an individual, but they supposedly only send catalogs to school addresses. I have heard of some who tried ordering from them and were turned down until he threatened to order from another company and then they let him order. Who knows? Science-type projects, kits & supplies (plastic molding equipment; radio/audio/video production; screen printing; lasers; hydrophonics; parts for all sorts of construction); cars, boats, planes, races, timers, bikes, magnetism, rocketry, hovercraft, balloons, wind tunnels, maglev; photography; bridgebuilding & testing; earthquake testing; robotics; plastic forming, injection molding, acrylic rods, acrylic sheets; signmakers; plastic, brass, copper, steel, aluminum, tin in tubes, rods, strips, channel and/or sheets; adhesive tapes; adhesives; paints; abrasive papers; clocks and parts; gears; motors; wheels; propellers; pulleys; magnets; solar cells; tools ( Dremel, Panavise, glue guns, scroll & band saws, lathe, [b] [i] mini-lathe, mini-vertical mill); badge/button maker; books; small kits; optics; scales; thermometers; timers; rulers; electronics trainers; test equipment; perf board; PCB layout software; wire wrap; PCB manufacturing (PCB material, Kepro shear, tin plating, ferric chloride, ammonium persulfate, etching tank, heater, Kepro spray etcher, transfers); soldering supplies (anti-seize, silicone grease); knobs, enclosures; potentiometers; connectors; switches; LEDs, capacitors (250v & 450v); resistors (1/4-w, power, SIP); integrated circuits (74xx, 74LSxx, 74HCxx, 4xxx, some linear and opto, some NTE); triacs; fuses; relays; IC sockets; transistors; transistor sockets; diodes (rectifiers, zeners, bridge); solder-type and screw-type phenolic terminal strips; barrier strips; crimp terminals; "Amphenol" microphone connectors; microphone cable; headphones; ferrite rod (10 cm x 8 mm); #18 thru #30 magnet wire; TV and computer accessories; batteries; battery holders; zip cord; solid & stranded hook-up wire; test lead wire; heat shrink; wire nuts; cable ties; electrical fixtures (lamp sockets, switches, receptacles, wall plates, plugs, electrical boxes, dimmers, lamp parts); cable clamps; spacers; rubber grommets.

Alltronics (This is one of those you-gotta-have-it catalogs)
2300 Zanker Road
San Jose CA 95131
408-943-9773 (voice)
408-943-9776 (fax)

Surplus electronics. LED flashlights; lens; "variac" variable autotransformers; transit cases; solar furnace; Teflon spaghetti; keychain laser; CPU heatsink; hard drive; solenoid valve; Loctite; carbide drill bits; 11-pin plug & socket - keyed; older crystal sockets; TO-3 transistor sockets; battery holders; Minicircuits parts; books; mobile antennas; grab bags (standoffs, plugs, trimpots, meters, shrink tube, resistors, MOVs, crystals & oscillators, capacitors, heat sinks, line filters, motors, motherboards, steppers, knobs, displays, ICs, torroids, hardware, wall warts, misc.); 45-to-33 spiders; tuners; tiny cameras; speakers; enclosures; capacitors (silver mica – excellent selection, polypropylene, polystyrene, axial electrolytic, axial tantalum -- excellent selection, conformal tantalum -- excellent selection, radial electrolytic); computer cables, computer accessories, LDC display; New-in-box Atari 1020 color printer ($14.95); fans; pumps; ear plugs; lacing tape and cord; syringes; Teflon tubing; PCB material (fantastic price!); integrated circuits (74xx, 74ALSxx, 74ASxx, 74Cxx, 74Fxx, 74Hxx, 74HCxx, 74HCTxx, 74Lxx, 74LSxx, 74Sxx, 4xxx, linear, used EPROM – overall, about the best IC selection I've ever seen in one spot other than an industrial distributor); little kits; LEDs – good selection; displays; #13 thru #40 magnet wire; magnets, ferrite beads, ferrite rod (0.5" x 8.875"); transformers; Amidon toroidal cores and other Amidon stuff; motors; steppers; pots; ultrasonic transducers; line filters; trimmer caps; rheostats; wall warts; solar cells; power supplies; prototyping boards; barrier strips; connectors & adaptors; muscle wire kits; surfboards; switches; heat sinks; a few tools; scope probes; rubber feet; diodes and transistors (nice selection); vacuum tubes (many used); instructional videos; cables.

Jameco Electronics (One of the good-to-have catalogs)
1355 Shoreway Road
Belmont CA 94002-4100
800-831-4242 (orders)
800-536-4316 (customer service)
800-455-6119 (technical support)
800-237-6948 (fax)
[email protected]

Computer accessories; solid state relays; small kits; integrated circuits (74xx, 74Cxx, 74LSxx, 74Sxx, 74HCxx, 74HCTxx, 6xxx, 4xxx, Intersil, Motorola, Signetics, linear, Maxim, Atmel, RCA, Z80, 6800, 8xx, A/D, D/A, EPROMs, EEPROMs, PROMs, PALs, GALs, RAM, memory modules, Analog Devices, Dallas Semi, PIC, ISD voice recorders); Parallax products; PIC products; software; prototyping; crystals; oscillators, diodes & transistors; CDS photocells (LDRs); varistors (MOVs); heat sinks; optocouplers; LEDs; IRLEDs & detectors; displays; LCDs; laser diodes; capacitors (trimmers, SMT, electrolytic, monolithic, tantalum, ceramic, mylar); resistors (1/8-, 1/4-, ½-watt, networks, SMT, potentiometers, trimpots); pressure sensor; flex sensor; hall effect; IR receiver modules; proximity sensors; temperature switches; knobs; switches; relays; connectors; cable clamps; buzzers; ultrasonic sensors; microphones; speakers; solenoids; steppers; motors; servos; gears; muscle wire accessories; batteries; fuses; solar panels; hardware; fans; line cords; line filters; transformers; "variacs"; wall warts (huge selection); power supplies (huge selection); books; breadboards; prototyping boards; enclosures; blank PCB; storage boxes and cabinets; little kits; cameras; PCB etching supplies; soldering equipment (Xytronix, Weller, Wahl, solder pots, fume extractors); chemicals; ESD tools; carbide drill bits; tools; test equipment; cables; EPROM programmers; computer parts (power supplies, keyboards, mice, cards, monitors, modems, hard drives, ZIP drives, floppies, motherboards, cases); computer accessories; network cabling and connectors.

Dalbani (If you do any consumer product repair, this catalog is a MUST!)
4225 NW 72nd Avenue
Miami FL 33166
800-325-2264 (voice)
888-716-9106 (fax)
[email protected].com

Deals primarily with consumer products repair. Semiconductors (STK, IRF, IRFZ, IRFP, STR, STRx, original manufacturer, huge selection of consumer ICs, diodes and transistors, rectifiers, NTE, ECG, TCG replacement semiconductors); capacitors (HV electrolytic to 450v); relays; resistors (1/4-w, power); computer components (cables, data switches, microprocessor cooling kits, cases, cable testers, monitors, cards, ethernet hubs, keyboards, mice, modems, printers, printer supplies, motherboards, hard drives, CD-ROMs, ZIP drives, blank CDs, speakers, microphones, accessories); multimedia training; VCR repair parts (pinch rollers, tuners, belts, heads, idler assemblies, tires, cassette housing assemblies, special tools); TV repair parts (flybacks, triplers, deflection yokes); CD player repair parts (optical pickup assemblies, capstans, jumper cables); potentiometers; TV antennas; video converters; video stabilizers; camcorder heads; MATV/CATV accessories; A/V cables; RG-6, 58, 59, 62 cable; power cables; connectors; adaptors; switches; IR remotes; camcorder batteries; LCD TVs; test equipment; analog & digital panel meters; scope probes & meter leads; soldering equipment (Soloman, Weller, Plato); chemicals; tools (nice selection, reasonable prices); parts cabinets & cases; security systems; A/V wall mount brackets; 2-way communication; home theater; headphones; microphones & accessories; batteries; electric shavers (I just report ‘em, I don't explain ‘em); cameras; telephones & accessories; telephone wiring, repair parts, cordless batteries; cellular batteries & battery eliminators; training videos; generic data books; power inverters; power supplies; wall warts; power cords; automotive sound (in-dash stereo, amplifiers, speakers, noise suppressors, antennas); crimp terminals; lamps; microwave oven magnetrons; NEC monitor replacement boards; small kits.

MCM Electronics (If you do any consumer product repair, this catalog is a MUST!)
650 Congress Part Dr.
Centerville OH 45459-4072
800-543-4330 (voice)
800-765-6960 (fax)
[email protected]

Home audio systems (power amps, preamps, receivers, CD changers, home theater, tube amp & solid state amp kits, speaker systems, Sovtek vacuum tubes, installation accessories, speaker switches); sound reinforcement systems (mixers, amplifiers, equalizers, active crossovers, speaker systems, road cases, microphones, mic accessories, speaker horns, snakes, windscreens, audio racks & rack accessories; disco crap); televisions; boom boxes; portable radios (AM/FM/SW); clock radios; stand-alone games; telescopes; binoculars; cameras; electronic flash units; tripods; camera cases; camcorder batteries; IR remotes; CD accessories; headphones; turntable cartridges & styli; test tapes and disks; VCR service tools; optical pickups; VCR repair parts; TV repair parts; automotive electronics (TV, antennas, in-dash stereos, EQs, power amps; crossovers, speakers, alarm systems, battery chargers, rear vision); batteries (alkaline, lithium, button cells, gel cells, NiMH, Renewal, NiCd); cordless phone batteries; flashlights (Streamlight, Mag Lite, Eveready); outlet strips/surge protectors; power cords; hospital-grade plugs and receptacles; cellular accessories and repair parts; chemicals; computer products (mother boards, Intel & AMD CPUs, memory modules, EPROM, cards, cameras, power supplies, hard drives, keyboards, mice, scanners, joysticks, speaker systems; disk storage systems, computer batteries, data switches); video game accessories; technician software; connectors & adaptors; crimp terminals; computer networking supplies; paper shredders; calculators; laser pointers; printer supplies; PCB etching supplies; prototyping supplies; breadboarding supplies; knobs; spacers; enclosures; relays; switches; incandescent lamps; LEDs; fuses; fuse holders; small kits; educational videos (UCANDO, EIA, more); books; satellite, MATV, CATV accessories & supplies; TV antennas (Winegard & Antennacraft products); security systems (surveillance & alarms); original equipment semiconductors; capacitors (HV radial & axial electrolytic, electrolytic, ceramic, tantalum, monolithic, film, variable); resistors (1/8, 1/4, ½, 1 carbon film, SMT, power, trimpots, panel pots); IC sockets; heat sink insulators; crystals (regular & low-profile); thermal fuses;vacuum tubes (limited number); books; ESD supplies; soldering equipment (Hakko, Weller, Tenma, Wahl, solder, solder wick); speakers, enclosures, parts, crossovers; storage cabinets, boxes & bins; adhesive tapes; magnifiers; vacuum cleaners; lighting; microfiche readers; tools (Panavise)

ABRA Electronics, Inc. (This is one of the good-to-have catalogs)
1320 Route 9
Champlain NY 12919
800-717-2272 (voice)
800-898-2272 (fax)
[email protected]

A large general catalog. Transistors (including SCRs, triacs, TIP series, IRF, Motorola); integrated circuits (including 74, 74LS, 4000, 74HC, 74HCT, 74HCTLS, 74C, 74F, 74S, 74ALS, 74ACT, linear, Exar, Maxim, Intersil, ADC, DAC, 8000, SRAM, PROM, EEPROM, 9000, 6000, EPROM, flash, DRAM, FPGA, Dallas Semi, GAL, PAL, memory modules, SMT devices); diodes (rectifier, zener, varicap, bridges); resistors (up to 22M, power, SIP, DIP, thermistors, potentiometers); capacitors (including electrolytic, tantalum, supercaps, film, HV caps, trimmers); lamps (including NE-2); optoelectronics (LEDs: blue, displays, holders, intelligent; MOC and 4N, H11, IR, matrixes, laser diodes); LDRs; DPMs; DMMs; analog panel meters; crystals; oscillators; noisemakers; fuses; fuseholders; IC sockets (ZIF, wire wrap, leadless carriers, PGA, SIMM, SIP); fans; heat sinks; switches (DIP, toggle, slide, rotary, micro); knobs; transducers; relays; relay sockets; inductors (a really nice selection); protyping; NTE replacement semiconductors (very comprehensive); maglites; xenon tubes & transformers; soldering equipment (

Omnitron Electronics
660 South Military Trail
Deerfield Beach FL 33442
800-379-6664 (voice)
954-574-9528 (fax)

Test equipment (Tektronix, Elenco, B&K, Fluke, Hitachi, misc., network test equipment); soldering equipment; test leads; tool kits; electronics trainers; laptop computers; computer equipment; training videos (UCANDO; hydraulics, servos, PLCs, rototics, relay control, misc.); small kits (Chaney, WizKits, Graymark).

Radio Shack
Ft. Worth TX 76102
(No mail-order; Internet or retail store sales only)

Electronics parts and consumer electronics. Radio Shack has the convenience of retail stores all over the country with the disadvantage of sometimes higher prices and alltimes limited parts values. For instance, they may carry a FEW SIP resistor packages, but not a good cross-section of values and styles. Stores vary in size and inventory. What you find in one store you may not find in another. In general, do not count on a Radio Shack employee to be at all knowledgeable in electronics. They may know stereos, TVs and computers, but don't know a thermistor from a thermocouple. Having their big catalog is nice for emergencies, but not for general orders. Their ":Cue:C.A.T." for interfacing their catalog with their Internet site is cute ... but you can't find the "free" device in any of their stores – they're always inconveniently "out". I understand that as of 2003, they will cease any use of a general catalog. If it isn't in the store, you won't find it.

POB 677
701 Brooks Ave., South
Thief River Falls MN 56701-0677
800-344-4539 (voice)
218-681-3380 (fax)

Despite the threatening name of their base of operations, Digi-Key, originally a hobbyist-oriented supplier, is becoming a player in the big distributor business. They have a broad line of solid state and passive components, and Panasonic is one of their largest brands. It's one of THE catalogs to have on hand. If you have a credit card or credit line with them, phone orders are received within four or five days.

Allied Electronics, Inc.
An Avnet Company
7410 Pebble Drive
Fort Worth TX 76118

This is one of the granddaddy distributors. Originally Chicago-based and selling the Knight-Kit line of hobbyist kits, they were bought by Tandy in the mid-1960s and headquarters moved to Ft. Worth. Radio Shack stores were renamed Allied-Radio Shack for a time. The 2"-thick catalog is a must to have at hand, for this is one of the sources that will carry what the others don't have. Allied has catalog sales offices all over the U.S.

Newark Electronics
4801 North Ravenswood Ave.
Chicago IL 80840-4496

This is another of the granddaddy distributors. Newark is still Chicago-based and it and Allied are direct competitors and have a nearly identical product line. Their 2"-thick catalog is also a must to have on hand, just as Allied's is. Newark has catalog sales offices all over the U.S. and they're linked with Farnell for worldwide sales.

Mouser Electronics
958 N. Main Street
Mansfield TX 76063
800-346-6873 (voice)
817-483-6899 (fax)

Mouser is a wannabe distributor. They have a lot of stuff, but are surprisingly deficient in some areas. Still a good catalog to have. A lot of magazine projects used Mouser-sourced parts.

The Electronic Goldmine
POB 5408
Scottsdale AZ 85261
800-445-0697 (voice)
480-661-8259 (fax)

Primarily surplus electronics with a changing inventory. Primarily surplus electronics with a changing inventory. Silicon solar cells, weird solder alloys (10/88/2, 40/60, 60/40, 63/37, 96/0/4), ultra-thin heating elements, limited types of semiconductors, air variable capacitors, carbide drill bits, wall warts, security electronics, antennas, rechargeable batteries, enclosures, test leads, ribbon cable, super caps, trimmer caps, Mylar caps, PCB material, crystal oscillators (regular and SMT), crystals, optoelectronics, ferrite cores, fans, heat shrink tubing, heat sinks, headphones, overstock electronic products, small kits, optics (lenses, mirrors, prisms), microphones, magnets, motors, piezo transducers, pots, relays, resistors (SMT, power, 1/4-watt, 1%), small robotics components, SMT (diodes, caps, ICs, resistors, inductors), IC sockets, switches, transformers, ultrasonic transducers, grab bags of all kinds.

Pasternack Enterprises
POB 16759
Irvine CA 92623-6759
949-261-1920 (voice)
949-261-7451 (fax)

Connectors, cables and connector adaptors. Not a bad catalog to have as a reference for identifying connectors. These are primarily RF connectors and they're pricey. More for the commercial end user.

Dean, Electronics Curmudgeon
Contributing editor emeritus in Poptronics magazine, R.I.P.

Dean Huster
Posts: 2219
Joined: Jan Thu 01, 1970 1:00 am
Location: Harviell MO USA 63945 (12 miles S of Poplar Bluff)


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The Breadboard Six Transistor Radio Kit

Whole Breadboard AM Radio             Kit Built Up

A complete kit of all the electronic parts shown is available, and the details of how to buy are shown right at the bottom of this page.

parts             included in the breadboard AM radio kit

The original choccy-block version of this radio kit that uses 3A screw-down terminal strips is shown here:  Choccy Block Transistor Radio.  It uses the same circuit but the kit is a bit more expensive and it takes longer to build that way.  This version also uses smaller 0.25W resistors and a plug-in volume control which suits this construction method.

Paper documentation is not provided.

Here is a link to a YouTube Video Demonstration of the Breadboard Radio Kit.

This is a MW AM  transistor radio which can be constructed without soldering using a standard small plug-in electronic breadboard. It is a modern response to the 1971 Ladybird Book Radio and works almost as well as some AM radios that you could buy in a shop. It's best to read right through the construction notes first before starting out. 

Link to PDF Schematic Of Breadboard Transistor Radio

Schematic Diagram of Breadboard Transistor Radio - Click to enlarge.

Choccy Block TRF             Radio Schematic Diagram

Bill Of Materials

Electronics Parts Included in the Kit. Click on the links for details.

Qty  Refs             Type                         Value

1    VC1              variable capacitor            200PF approx
1    L1               ferrite rod d=9.5mm l=100mm   see text

2    R1,R3            resistor                      1K
1    R11              resistor                      470R
1    R12              resistor                      1.8K
3    R2,R4,R8         resistor                      6.8K
1    R7               resistor                      12K
1    R9               resistor                      27K
3    R5,R14,R15       resistor                      47K
1    R10              resistor                      100K
1    R6               resistor                      330K
2    R13, R16         resistor                      220R

1    VR1              volume pot pcb                10K
1    C9               ceramic capacitor             68pF
5    C1,C2,C3,C4,C5   ceramic capacitor             10NF
1    C6               ceramic capacitor             100NF
1    C7               electrolytic capacitor        10UF
1    C8               NP elec capacitor             4.7UF
3    C10,C11,C12,C13  electrolytic capacitor        100UF

2    D1,D2            diode                         1N4148

1    Q4               NPN audio transistor          BC549C
1    Q3               PNP audio transistor          BC560C
1    Q5               NPN driver transistor         BD139
1    Q6               PNP driver transistor         BD140
2    Q1,Q2            NPN RF transistor             BF199


1    LS1              65mm 8R loudspeaker       
1    J1               PP3 battery clip
1    S1               slide switch pcb
1                     plug-in breadboard
1                     3A 3-way terminal strip
2                     M2.5 bolts 4mm
4                     M2.5 washers
2                     short shaft control knob
1                     single core wire 4m

Extras Not Supplied

Paper glue
Small screwdriver
Sticky tape
Small wire cutters
Craft Knife
PP3 9V Battery

Link to PDF of BOM for Choccy Block Transistor Radio



I supply a kit of all the electronic parts, wire and breadboard. I've assumed that you have a small screwdriver for the terminal screws, some small wire cutters for trimming the component leads and some means of stripping the insulation from the wire.  A craft knife is good for that.  You will also need some paper, glue, scissors and sticky tape. 

What do you Need to Know Before You Start?

The components list has links to photographs that should allow you to make sense of the different values and to identify which leg is which.  You need to know about resistor colour codes and you can find that information in many places.  It should be possible to build the radio just by looking at the pictures, but later on I've included full electronic explanations.  If those don't make any sense, don't let them put you off just building the circuit.

The schematic diagram can look a bit daunting to the novice.  Don't Panic.  You don't need to understand it all to make it work.  The idea of this design is that if you follow the plan it should work without too much fiddling.  Experienced builders will find the schematic diagram helpful as well. 

How To Build It: Follow the Pictures and Schematic Diagram

The main pictures taken from directly above in plan view will show where everything goes most of the time.  There are more pictures taken from different angles later on, if the main ones are not clear.  This might happen where one wire may have covered up the exact plug-in position of one underneath it.  Where the plug-in hole is obscured by the component, it is marked on the picture by an "X"
Assemble the Resistors

Breadboard TRF Radio with           Resistors Inserted

Start by plugging the resistors into the correct holes in the breadboard as shown.  They should be cut to length so that they sit flat against the board when plugged in.  This stops them wobbling about and avoids having long legs shorting out against other wires.  The resistors can be plugged in either way around, but it makes it easier to check the colour codes if they are inserted the same way around as shown in the picture.  You can click on the pictures to see a bigger version.

Assemble the Capacitors and Diodes

Breadboard TRF Radio with           Resistors, Capacitors and Diodes Inserted

Identify the ceramic capacitors, the electrolytic capacitors and the diodes and fit them as shown.  The diodes have to be plugged in the right way around, as identified by a black band at one end of the glass case.  With the exception of the bipolar one, the electrolytic capacitors have to be connected the correct way round as indicated by a white stripe with a "-" negative symbol on the negative side.
Assemble the Transistors. 

Breadbaodr AM radio           project with Resistors, Capacitors, Diodes and Transistors           Fitted

Fit the six transistors as shown.  They all need to be the correct way round as identified by the flat side on the small ones and the plastic side with the type number on for Q5 and Q6.  The leads of Q5 and Q6 are quite large for the breadboard holes so ease them in gently to avoid damaging the internal spring contacts.

Assemble the Loudspeaker, Wire Links, Battery Clip, VR1, SW1.

MW Radio on Prototype           Board Complete Components Detail

The on-board wire links are made by cutting approximate lengths of the single core wire supplied and stripping about 5mm of insulation from each end using a conventional wire stripper or by scoring around the insulation with a craft knife and pulling the small piece of insulation off.  Use an appropriate level of care with craft knives;  They are razor sharp.  The volume control VR1 needs to have the pins bent as shown so that it will plug into the board pointing out sideways. 

Spekaer wires passed           through the tah hole and crimped with pliers

You need to connect two lengths of wire to the loudspeaker by passing it through the terminal hole one or twice and crimping it down firmly with pliers to make a good connection.  The other ends can then be plugged into the board as usual.

Wind and Connect the Antenna Coils

The input coupling coil is the small one which takes the signal from the ferrite rod and feeds it into the radio.  This is constructed as follows.  First make a paper tube about 2.5cm long.  Use a strip of some normal printer or magazine paper about 2.5cm X 10cm.  Put stick glue on about 8 of the 10cm length then wrap this around the ferrite rod so that the glue sticks the paper and forms the tube.

Coupling Coil Former           Glue PosistionCoupling Coil           Former Roll StartComplete Coupling           Coil Paper Former

After this has dried, using single core PVC insulated copper wire, wrap 6 turns onto the tube.  Secure the start end with sticky tape first and then the far end when it is complete.  You can follow the photographs which show this process.  Don't wrap the paper, the wire or the tape too tightly or you won't be able to slide the coil up and down the rod.  I recommend winding the wire by rotating the rod and former rather than wrapping the wire around.  Wrapping it around tends to put a twist in the length of the wire which makes it tangle up more easily.

Coupling coil wire           taped and winding startedTRF Radio Coupling           Coil Complete

The main MW tuning coil is the large one which is connected to the tuning capacitor.  The paper tube for this is made from paper 6cm X 10cm.  First wind the coil in one direction across the tube for about 25 turns and then 20 turns over the original turns coming back in the other direction. 

Main TRF Tuning Coil           Winding StartMain MW Radio Coil           Winding StartedMain Tuning Coil Halfway
Main Coil           Overwinding StartMain MW AM Coil Almost           CompleteCompleted MW Tuning           Coil on Ferrite Loopstick

Connect the Variable Capacitor VC1 to the Main Coil

Looking at the variable capacitor from the bottom side, the side without the control shaft, you will see two trimmer screws and the three strip connections.  The two trimmer screws add extra fixed capacitance to the variable elements.  They should be adjusted as shown in the third photograph for minimum extra capacitance.  This is the position where the semi-circular moving plates attached to the screws are clear of the lower metal plates.

Variable capacitor trimmers               set to maximumtuning capacitor trimmers               set to halftuning capacitor trimmers set               to minimum

The middle strip is the common ground for the two capacitors and the outer strips are the remaining connections.  As supplied, the connection strips exit at the side nearest to the top face of the capacitor.  To fit it into the terminal strip you need to remove the transparent plastic case of the variable capacitor, and unfold the strips so that they go out of the holes in the bottom face, as shown in the picture sequence.

Plastic AM Capacitor As             SuppliedVariable Capacitor With the Back Cover             Removed To Move the LeadsCapacitor Connection Strips As Required             for connection into terminal strip

VC1 connects only to the main MW coil using the three-way terminal strip provided.  The link wire between the two outer terminals connects the two variable capacitors inside the case together to work in parallel. 

VC1 Wiring                 pre-assemblyVariable Capacitor Connected to Main Coil Using                 Terminal StripTRF Radio Coil Connection Detail

The smaller of the two coils connects into the breadboard as shown in the picture.

That’s It, but Have a Check Around

If you've gone stage-by-stage and everything is in the right place, it should be ready to go.  It's worth double checking the direction of the two diodes, the transistors and the electrolytic capacitors. 

Starting Up and Initial Testing
Connect the battery, move the slider of SW1 to the end nearest to the two connected wires and rotate the volume control up to about halfway. Turning the tuning control should immediately allow you to hear the main MW stations.
The Completed Radio

The Completed Breadboard MW AM           TRF Radio

Now that it's all together, you can count how many AM stations you can pick up, bearing in mind that the antenna is directional so you have to rotate the radio for the best signal.  If you find that you are missing the high frequency end of MW you can move the main tuning coil closer to the end of the rod, shuffling up the coupling coil to meet it.  How good is it compared to something bought from the shops?  The three models that I have made up are all of identical performance and I think that it compares well with a small shop radio.  The tuning is sharp enough to distinguish the three Absolute Radio frequencies of 1215, 1242 and 1260 kHz in Farnborough, Hampshire UK which is good going for this simpler design.  There's no need for external aerial wires as with some home constructed designs.  The audio amplifier drives the small loudspeaker to a good volume.

My Radio Isn't Working.

Most probably, something is in the wrong hole.  It can be useful to make a colour print-out, place it by the side of the real thing and play spot-the-difference.  Have another look for shorts between components where they are where they are close to other wires.  Check the resistor colour codes as it's easy to neglect those once you've decided that you've chosen the right part and plugged it in.  My favourite mistake is getting the output driver transistors Q5 and Q6 swapped over and one or both of the diodes the wrong way round.  If you've got a multimeter, use the 10V voltage measurement range to check around the d.c. voltages when tuned away from a station.  With a fresh 9V battery you should see voltages that are very close to those marked on the schematic diagram.  Very close in this instance means within plus or minus 0.3V of the figure in the diagram.  The voltages marked on the schematic diagram are measured values for direct connection of 9.0V power with low signal input, all with the negative meter lead connected to the negative battery terminal.  If you see a voltage that is more than about 0.3V out either way, then there is probably something wrong in the circuit around that transistor.  If all voltages look low, the battery rail is probably shorted out in some way.  If you have intermittent operation that comes and goes with vibration or handling, gently prod the various parts of the circuit until you find the sensitive part.  There will usually be a wire loose or shorted in that area.

The area around Q2 and C5 is quite sensitive to interference from nearby wiring.  If you find that the radio is working but is very hissy or squeals, try moving the coupling coil up the ferrite rod a small distance away from the main coil.

If you can't get it going at all, please email me at the email address shown at the bottom of the page.  You'll need to be prepared to send well-focussed, good quality pictures of the details of the breadboard from several angles, and of the whole construction.  I will usually be able to get you going. 

End Of Construction

That's the end of the construction notes, and is as far as you have to read if you just want to build the radio.  What follows is some more in-depth technical description and design philosophy discussion for the electronics engineers.  After that there is a FAQ which may be useful if you're still having problems getting going, or if you've bought all your own components.  If you fancy trying some further modifications, there's a page with some ideas on too.

Design Philosophy

As noted at the top, this is intended to be a modern replacement for the 1971 Ladybird Book "Learnabout: How to Make a Transistor Radio" radio.  I've described elsewhere how I didn't have much success with this as a kid, mostly due to the problems with 1960s transistors and their substitutes in a simple design.  I have made up kits of parts for the 1971 G.C.Dobbs design but I didn't want to encourage the use of germanium transistors and LT700 output transformers.  I propose this design as an alternative.  It is more complex and has twice as many transistors, yes;  But with the additional complexity it works better, it is more consistent, you can get all the parts, and it is cheaper. 

Why do we need another design for a simple AM radio when there are already so many? 

Although there are many designs around, none of them seemed to bring together all of the points below.

Uses entirely cheap modern components.
Is very insensitive to any component variation.
Has no integrated circuit black box components.
Can be built with a solderless assembly scheme.
Has no fiddly adjustments.
Uses design principles which can be fully explained.
Uses no funny electronic tricks.
Works as near as possible to something that you might buy from a shop.

Breadboard Construction

I've started from the assumption that soldering puts many people off electronic projects.  A good soldering iron isn't cheap, burns the inexperienced quite readily and will set fire to the house if it doesn't have a proper stand and falls off the desk if left switched-on unattended.  It requires a small amount of skill too.  The plug-in breadboards are not perfect but they are very quick and easy to use.  The availability of these small, cheaper plug-in boards makes this construction method a quicker alternative to building on terminal strips as shown in the choccy-block radio.  If you want to try plugging in different transistors, coils, speakers etc, it's much quicker on the breadboard.

Breadboard Transistor Radio Detailed Circuit Description

Breadboard Transistor Radio FAQ

Breadboard Radio Additional Pictures.

Breadboard Radio Modifications and Extras

A complete kit of electronic parts is available on Ebay at the following link, where overseas shipping options are also available:

Solderless Breadboard Six Transistor MW AM Radio Kit Of Parts Ebay Search Link       Ebay Item Number 111259107754 Direct Link

Useful Components Ebay Shop

If ebay are blocking this listing in your geographical area for their own nefarious reasons, you can also get it on Etsy:

Six Transistor AM Radio Kit Of Parts Using Solderless Breadboard To Make MW Receiver with Fully Detailed Online Instructions   Etsy Listing Number 925834619

Should you have any problems or questions, my main email address is shown below.  This address has been the same since 1997 and unless I'm on holiday beyond mobile coverage, it is checked daily including the spam folder.

 Henry's Main Email Address

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 © Henry J. Walmsley 2014.

Fault Finding \u0026 Repair Of A Transistor Radio

Three Transistor Radio Parts List

Parts and Components

The cost of components and parts is forever increasing, and therefore it is logical to recycle some of the parts you may already have. Whilst components such as the loudspeaker and variable capacitor may not be so critical, the fixed ceramic disc capacitors are. In particular, C1, C2, and C3 maintain the bandwidth of the high-gain amplifier. The values shown fix it to receive signals within the medium wave (MW) band. Changing these will change the characteristics of the amplifier stages.


The value of capacitor C1 at the base input of Q1 is extremely critical and must be 47 pF. The ceramic disc marking will be "47". Capacitor C2 is also critical as it ensures that the transistor amplifies signals in the MW band. The marking on the capacitor should be "104" which represents 100000 pF, which is 100 nF, or 0.1 uF.

Capacitor C3 (marking 104J) performs a number of tasks. Firstly, it earths any radio frequency (RF) signals that may have made it this far. At this final stage, we do not require any RF, and transistor Q3 amplifies only audio frequency (AF). It also removes some of that sharp high frequency hiss but leaves the bass, which makes it sound extremely nice if you had a good pair of headphones.

Volume Control

The volume control is a 10 kΩ logarithmic potentiometer. It is very rough and ready because on one side, you get a lower volume without the treble, thanks to C3, and on the other end, you get a high volume with full treble.

This radio does not have an automatic gain control (AGC) and you get to hear the signal exactly as it arrives. This means that the signal from some of the distant radio stations will be weak, and you will need to have the volume to a mid level. However, tuning to a nearby station with a strong signal will produce extremely loud audio and you will need to turn the volume to a low level.

When tuning through stations, keep the volume low, and increase it gradually after you have selected the station.



This Article Continues...

Three Transistor Radio - Whippersnapper 2
Circuit Diagram
Ferrite Coil Antenna
Loudspeaker and Transformer
Variable Capacitor
Baseboard Layout
Parts List
Completed Build


Radio parts transistor


Vintage Ross Transistor Radio Repair


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