Rap 'n Tap
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From: Philip Miller Tate
Date: 6/9/00
Time: 7:55:10 AM
Remote Name: 141.241.36.84
Scot: here is the answer you really want. Assuming you have a soldering iron, go to:
http://www.poptronix.com/articles/index.html
Scroll to the bottom of the page, click on 'Inductance Meter Adapter'. You need Acrobat Reader. Build the circuit. It uses 2 cheap ICs, is dead simple, and it works. You MUST use a 74HC132, non-CMOS TTL gates won't oscillate. Don't mess about with a printed circuit board, kludge it together on stripboard. Remember to buy in some cheap inductors for calibration purposes (100, 220, 470uH, 1, 2.2mH). It ain't terribly accurate, it runs into difficulties towards the end of each range, but it works and is more than adequate for radio work. Best four hours' work I ever did, building mine (after months of 'bridge' circuits that were all useless).