Heathkit

IT-3121 Curve Tracer

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How to search

sten gun
pages with both words
"sten gun"
the words together, as a phrase
sten OR sterling
either one (| works too)
sten -replica
leave out pages that mention “replica”

Without quotes, the last word also matches longer words that start with it (sten finds Stenophylla), and close word forms count (rifle finds rifles). Tick Exact words to match whole words only.

Other words for the same thing are searched too (uniselector also finds stepping switch), ranked below pages with your own words; the results say what else was searched. Quotes or Exact words turn that off.

Whole deep dives are listed first, then the pages inside them. Click a topic under the box to narrow the results.

Tick Photos to search the captions of every photo and diagram; each picture opens where it sits in its volume. The Show row narrows to one kind of result: volumes, deep dives, photos, parts lists, Library documents or downloads.

    Volumes

    1. Vol 1 What It Is and Its Place in the Heathkit Line The affordable semiconductor curve tracer that put device fingerprinting on the hobby bench
    2. Vol 2 How a Semiconductor Curve Tracer Works Stepped base drive, swept collector supply, and an X-Y plot — the IT-3121 as the worked example
    3. Vol 3 Servicing It, and Dave Erickson’s Redesign What breaks on a 40-year-old unit, and how Dave Erickson rebuilt the architecture with a microcontroller
    4. Vol 4 Using It: Procedure, Reading Curves and Safety Wire up a scope, and read gain, breakdown, and matched pairs off the glass