ET-3100 Analog Trainer · Volume 6
Reference
This volume collects the specifications, parts data, prices, manuals and course documents for the ET-3100 family in one place. Where the manual and the catalogue disagree, both are given.
6.1 Full specifications: ET-3100 and ET-3100A
From the ET-3100 manual (595-1734-06, p. 28). Eckweiler reports the ET-3100A manual’s figures as identical (HotM #129, Table I).
Table 1 — Full specifications: ET-3100 and ET-3100A
| Positive supply output | 1.2 to 15 V DC, continuously variable |
| Load regulation | better than 1%, no load to full load |
| Current output | 100 mA with short-circuit protection |
| Negative supply output | −1.2 to −15 V DC, continuously variable |
| Load regulation | better than 1%, no load to full load |
| Current output | 100 mA with short-circuit protection |
| Signal generator range selector | LO 200–2000 Hz, HI 2000–20,000 Hz, continuously variable |
| Sine wave output | 1 V rms from 600 Ω at less than 4% distortion |
| Square wave output | 15 V p-p (+15 V maximum, 0.1 V minimum), rise time under 1 µs, nominal duty cycle 30% |
| 60 Hz sine wave output | 15 and 30 V rms |
| Current | 200 mA maximum (total current from all supplies must not exceed 200 mA) |
| Power requirements | 105–130 V or 210–260 V rms, 50–60 Hz, 7 W maximum |
| Dimensions | 12⅛ in wide × 11¾ in deep × 3½ in high |
| Net weight | 4 lb (shipping 5–6 lb) |
Catalogue figures that differ (Christmas 1975 to Winter 1981–82): supplies “variable over 1.2 to 16 volts, current rating 120 mA”; sine distortion “less than 1%” (Christmas 1975 only); breadboard “96 terminals with 5 common connections each, arranged as 48 pairs”. The Fall 1979 and 1980 catalogues printed the manual’s 100 mA figures in a specification box beside copy that still said 120 mA. The circuit volume explains both numbers.
6.2 Full specifications: ET-3100B
From the ET-3100B manual (595-2860-03, p. 34). Differences from the ET-3100 in bold.
Table 2 — Full specifications: ET-3100B
| Positive supply | 1.2 to 15 V DC, continuously variable; 2% load regulation; 250 mA with short-circuit protection |
| Negative supply | −1.2 to −15 V DC, continuously variable; 2%; 250 mA |
| Frequency generator | LOW 200–2000 Hz (nominal); HIGH 2000 Hz–20 kHz (nominal) |
| Sine / square | as ET-3100 |
| 60 Hz outputs | 15 and 30 V rms, 200 mA maximum (separate winding) |
| Power | 105–130 or 210–260 V, 50/60 Hz, 25 W maximum |
| Dimensions | 12⅛ × 11¾ × 3½ in (30.8 × 29.9 × 8.9 cm) |
| Weight | 4.2 lb (1.9 kg) |
6.3 Semiconductor complement
Table 3 — Semiconductor complement
| Function | ET-3100 / ET-3100A | ET-3100B |
|---|---|---|
| Oscillator | IC1 741 (442-22: N5741V, MC1741CP1, HA7417C or LM741CN) | U1, U2 LM301 (442-39) |
| Sine buffer / squarer | Q1 MPSA20 (417-801), Q2 2N4121 (417-235), Q3, Q4 MPSA20 | Q1, Q2 MPSA20 |
| Squarer / bias diodes | D1, D2, D3 1N4149 (56-56) | D1, D2 1N4149; ZD1, ZD2 1N5223B 2.7 V (56-99) |
| + supply pass | Q101 MPSA20 + Q102 MJE181 (417-818) | Q101 MPSA20 + Q102 MJE5979 (417-856) |
| + error amp / limit | Q103, Q104 MPSA20 | Q103, Q104 MPSA20 |
| − supply pass | Q105 2N4121 + Q106 MJE171 (417-819) | Q111 2N4121 + Q112 MJE5976 (417-857) |
| − error amp / limit | Q107, Q108 2N4121 | Q113, Q114 2N4121 |
| References | ZD101, ZD102 15 V zener (56-620) | ZD101, ZD111 1N4744A 15 V (56-620) |
| Offset diodes | D106, D107 1N4149 | D106, D116 1N4149 |
| Rectifiers | D101, D102, D104, D105 1N4002 (57-65) | D101–D104 1N4002 |
| Pilot | PL101 neon lamp (412-15), 27 kΩ (ET-3100); red LED, 1 kΩ (ET-3100A) | V101 LED LST5053 (412-640), 1.8 kΩ |
| Oscillator AGC | L1 incandescent lamp (412-83) | none |
6.4 Principal parts
Table 4 — Principal parts
| Part | ET-3100 | ET-3100B |
|---|---|---|
| Power transformer | 54-892, dual primary, 30 V CT 200 mA | 54-1005, dual primary, two secondaries |
| Circuit board | not legible in the scan examined | 85-2730-1 (brown); -3 (white) also made |
| + / − VOLTAGE controls | 3 kΩ (10-1053) | 3 kΩ (10-1053) |
| FREQ control | 100 kΩ dual (12-146) | 200 kΩ / 5 kΩ dual (12-184) |
| Feedback trimmer | R4 1 kΩ (10-391) | — |
| Experimental controls | 1 kΩ (10-1054), 100 kΩ (10-1055) | same |
| RANGE switch | DPDT slide (60-78) | same |
| Power switch | SPST rocker (60-607) | same |
| Connector blocks | 15 × 432-874 | same |
| Breadboarding socket | 432-875 | same |
| Fuse | 1/8 A slow-blow in clips | 1/4 A slow-blow (421-33) in holder (423-11) |
| Line cord | two-wire (89-49), knotted | three-wire (89-54) with strain relief |
| Reservoir capacitors | 1000 µF (25-876) per parts list; 1200 µF 30 V on schematic | 1000 µF (25-876) |
6.5 Prices, catalogue by catalogue
Table 5 — Prices, catalogue by catalogue
| Catalogue | ET-3100 kit | ETW-3100 | Course packages |
|---|---|---|---|
| Christmas 1975 | $59.95 | — | EE-3101/2/3 $39.95 each; each with trainer $89.95; all three with trainer $154.95 |
| Spring 1976 | $59.95 | — | ETS-3100 (three courses and trainer) $154.95 |
| Fall 1977 | $59.95 | $89.95 | EE-3104 $49.95; EES-3104 $99.95; ETS-3114 (four courses and trainer) $199.95 |
| Christmas 1977 | $59.95 | $99.95 | |
| Spring 1978 | $64.95 | $109.95 | |
| Fall 1978 | $64.95 | — | EE-3101 $44.95; EES-3101 $99.95 |
| Fall 1979 | $69.95 | $129.95 | EE-3101/2/3 $44.95; EE-3104 $54.95 |
| 1980 (No. 848) | $69.95 | $129.95 | ET-3100-S Spanish kit listed |
| Winter 1981 | $79.95 | $139.95 | EES-3101 (with kit) $119.90 |
| Winter 1981–82 | ET-3100A $79.95 | ETW-3100A $139.95 | ET-3100AS $99.95; EES-3101A $119.90; EE-3106 $59.95 |
| Christmas 1982 | ET-3100B $84.95 | ETW-3100B $149.95 | EE-3101A $49.95; EES-3115B (five courses and trainer) $324.70 |
| Fall 1983 | ET-3100B $99.95 | — | EES-3101B $129.90 |
| Fall 1985 | ET-3100B $109.95 | ETW-3100B $179.95 | 10% off “this catalog only” |
| Fall 1987 | ET-3600 $119.95 | ETW-3600 $199.95 | ETW-3100-B still offered |
All from the general Heath catalogues at World Radio History. Heath’s school and institutional prices, on separate price lists, are not included.
6.6 Related Heath products
- ET-3200 / ET-3200A / ET-3200B Digital Design Experimenter (1975): the digital sibling, for EE-3201 Digital Techniques. See the ET-3200 dive.
- ET-3400 / ET-3400A Microprocessor Trainer (Christmas 1977): 6800-based, for EE-3401. See history dive, vol. 5.
- ET-3300 / ET-3300A Breadboard: a larger breadboarding station sold for Heath’s advanced courses. The Winter 1983 catalogue accepts “ET-3300A or ET-3100B” for some courses but notes that the ET-3100B “cannot be used with other courses in Advanced Series” (Winter 1983, p. 34).
- ET-3600 / ETW-3600 Analog Trainer (Fall 1987): the successor. By the 1990s it was rated at 250 mA per supply with a 5 V rms sine output and a 45–55% square wave, had a removable breadboard block (ETA-3600-1 extra blocks) and accepted the ET-3567 Accessory Backpack and ETB experiment boards. It was specified for every course in the old ET-3100 series, now in EB-6101-A to EB-6106 classroom texts, EE-3101-B to EE-3106-A self-study editions and CAI-610x computer-aided versions.
- Meters named by the courses: IM-17 VOM (1975), IM-5284 (1978), IM-5217 (1982), IM-2260 (1983); oscilloscopes IO-4541 (1977) and IO-4105 (1982).
6.7 Manuals and documents
The ET-3100 is on the list of Heath titles that Tubular Electronics withholds as still in copyright (Tubular Electronics), and under decision 5 of this project it is link-only: nothing below is hosted on this site. The links point to third-party copies.
Table 6 — Manuals and documents
| Title | Part number | Date | Copyright notice | Free scan |
|---|---|---|---|---|
| Heathkit Manual for the Electronic Design Experimenter, Model ET-3100 | 595-1734 (printing -06 examined) | © 1975 on title page; -06 printing carries the Heath/Zenith rear-cover logo, so c. 1980 or later | Yes: “Copyright © 1975 Heath Company, All rights reserved” | Internet Archive (DLARC manuals): https://archive.org/details/manualsplus_11837 |
| Schematic of the Heathkit Electronic Design Experimenter Model ET-3100 (Illustration Booklet sheet) | “Part of 595-1734-02” | © 1976 | Yes | https://archive.org/details/heathkit_et-3100 (heathkitmanuals); https://archive.org/details/HeathkitET3100ElectronicDesignExperimenterschematic_201502; https://archive.org/details/Heathkit_ET-3100_Electronic_Design_Experimenter_Signal_Generator (five pages from the same sheet); OCARC: https://www.w6ze.org/Heathkit/ET-3100/index.html |
| ET-3100 parts list | — | — | not examined | OCARC: https://www.w6ze.org/Heathkit/ET-3100/index.html |
| ET-3100A manual | not found | c. 1981 | — | No scan found. Schematic and parts list (from N8FH) at OCARC: https://www.w6ze.org/Heathkit/ET-3100/index.html |
| ET-3100-S / ET-3100AS Spanish manual | not found | c. 1980–82 | — | No scan found |
| Heathkit Manual for the Electronic Design Experimenter, Model ET-3100B | 595-2860-03 | © 1982 | Yes: “Copyright © 1982 Heath Company, All Rights Reserved” on title page and Illustration Booklet | Internet Archive (DLARC, Cal Poly Amateur Radio collection): https://archive.org/details/heathkitmanualfo00unse_0 ; schematic and parts list also at OCARC |
Hosting-rule data. None of these titles qualifies for hosting under the project’s public-domain tests, independently of the Tubular Electronics listing. All were published after 1964 with a copyright notice. For works first published between 1964 and 1977 with notice, renewal became automatic under the Copyright Renewal Act of 1992, so a renewal search in the Catalog of Copyright Entries would not change the result for the 1975 manual or the 1976 schematic; works first published from 1978 onward with notice, such as the 1982 ET-3100B manual, need no renewal. No renewal search was carried out. Status: link-only, and never to be presented as hosted here.
6.7.1 Course documents
These are course materials rather than kit manuals, listed because the trainer cannot be understood without them. All are link-only; all carry Heath copyright notices of 1975 or later.
Table 7 — Course documents
| Title | Number | Edition / date seen | Free scan |
|---|---|---|---|
| DC Electronics (Individual Learning Program) | EE-3101; instruction sheet 595-1781-04; records 449-115 | c. 1983 binder scan | https://archive.org/details/ee-3101-dc-electronics |
| DC Electronics, fifth edition | EE-3101-C, 595-5799, ISBN 0-87119-275-6 | © 1998, 1989, 1982, 1975 | https://archive.org/details/ee-3101-c-heathkit-dc-electronics-individual-learning-textbook-1999 |
| AC Electronics, fourth edition | EE-3102-C, ISBN 0-87119-276-4 | © 1999, 1989, 1982, 1975 | https://archive.org/details/ee-3102-c-heathkit-ac-electronics-individual-learning-textbook-1999 |
| Semiconductor Devices, third edition | EE-3103-B, ISBN 0-87119-210-1 | © 1998, 1989, 1982, 1975 | https://archive.org/details/ee-3103-b-heathkit-semiconductor-devices-individual-learning-textbook-1999 |
| Electronic Circuits, third edition | EE-3104-B, ISBN 0-87119-211-X | © 1998, 1990, 1982, 1977 | https://archive.org/details/ee-3104-b-electronic-circuits-individual-learning-system-textbook-1998 |
| Semiconductor Devices Lab Book (classroom, ETW-3600) | EB-6103-71 | c. 2001 | https://archive.org/details/eb-6103-71-heathkit-semiconductor-devices-lab-book |
Records for the first five courses carried part numbers 449-115 (EE-3101) to 449-119 (EE-3201), per the 1983 EE-3101 instruction sheet.
6.8 Catalogues consulted
General Heath catalogues at World Radio History: Christmas 1975; Spring 1976; Christmas 1976 (No. 813, no text layer, not searched in full); Fall 1977 (No. 817); Christmas 1977; Spring 1978; Fall 1978; Winter 1978; Fall 1979; 1980 (No. 848); Winter 1981; Christmas 1981; Winter 1981–82; Christmas 1982; Winter 1983; Fall 1983; Fall 1985; Fall 1987. Also the Heathkit/Zenith Educational Systems & Instruments retail catalogue 811-29R, filed by World Radio History as 1975 but internally datable to about 1980–81 (see the courses volume). The 1974 catalogues (March 1974 and No. 810-74) were checked and do not list the ET-3100 or the courses.
Further reading
- Bob Eckweiler, AF6C, Heathkit of the Month #129, “Heathkit ET-3100/A/B Electronic Design Experimenter/Trainer (and Associated Heath Offered Courses)”, Orange County Amateur Radio Club, rev. 1, January 2026. The only detailed modern account, especially valuable for the ET-3100A and for the course history: https://www.w6ze.org/Heathkit/Heathkit_129_ET3100B.pdf. The OCARC support page has schematics and parts lists for all three versions: https://www.w6ze.org/Heathkit/ET-3100/index.html
- heathkit.nu, “ET-3100 The Breadboard Circuit Design Trainer”: a Swedish owner’s page on the Esselte OEM version and its modification. Its statement that the ET-3600 replaced the ET-3100 “in the early 90’s” is contradicted by the Fall 1987 catalogue. http://heathkit.nu/heathkit_nu_ET-3100.html
- W0MPM, “Heathkit ET-3100 Experimenter and Breadboard”: a modern owner’s improvements. https://qsl.net/w0mpm/HeathkitET3100.html
- Jeff Tranter, a video on the ET-3100A, cited by Eckweiler: https://www.youtube.com/watch?v=X9haztHTCsg (not reviewed for this dive).
- Radiomuseum.org, ET-3100 entry, with owners’ photographs: https://www.radiomuseum.org/r/heath_et_3100_et310.html. Its year (1981) and its “20 Hz to 20 kHz” generator range are both wrong.
- The Heath Company history dive on this site, for Heathkit Educational Systems and the Zenith years: https://heathkit.fubsypoly.com/heathkit/vol-4/, https://heathkit.fubsypoly.com/heathkit/vol-6/ and https://heathkit.fubsypoly.com/heathkit/vol-7/
Sources
All sources are linked inline above. The primary documents are the ET-3100 and ET-3100B assembly manuals and the Heath course texts held at the Internet Archive, and the Heath catalogues scanned by World Radio History. The principal secondary source is Bob Eckweiler’s Heathkit of the Month #129.
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