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dmyers
05-22-2006, 10:41 AM
My dad (which is also in electronics) just brought over his benchtop multimeter he got from Radio Shack about 5-10 years ago (could be more knowing him). Never the less I was floored to see it figure out a transistor type and gain with only 3 holes! I looked it over and knowing I have a box of transistor I knew nothing about I plugged one into the 3 holes pressed the button and instanly it said NPN for 2 seconds then EBC for 2 seconds and then .45 (or what every the gain was). I simply could believe it. I then looked all over the internet for a simple 3 hold design with no luck! Every one has 8 hole designs. This thing was designed 10 years ago and could do it.

I began to think there has got to be a way to do this with today's basic stamp but, I don't know where to start? Does anyone have any ideas on how to design a simple transistor tester that would only use 3 stamp inputs and display (to the terminal) the type either as NPN or PNP, legs EBC, CBE, BEC, etc.... and gain?

I can't image there being any fancy chips in that box since it's so old. I almost wanted to take it apart!

Next time he said he would bring over his customer power supply. He know I smoked my last one by accident.

D Myers.

Scott Knauert
05-23-2006, 01:56 AM
Take a look at the schematics here: http://sound.westhost.com/project31.htm Its an old-school 3 terminal transistor tester with full plans. I'm sure you could automate the tests and use digital pots and voltmeters to get the results. The PNP/NPN section on that project could easily toggle a pin to let you know. If you need to know ECB status, and you have a digital voltmeter and a 3x3 matrix of relays you could test ECB status via measuring resistance before the gain test. Technically this could be worked into a PNP/NPN test with some logic before the gain test.

Hope this was helpful.

Edit: Trying to test ECB with gain testing, even under low current, is a bad idea.

Post Edited (Scott Knauert) : 5/22/2006 7:03:20 PM GMT

dmyers
06-17-2006, 05:15 AM
Wow thank's to ebay I was able to buy the same "super" meter as him with orginal instructions and probes and get a additional 8 function multimeter with instructions and probes for less than the cost of a basic stamp 1!

cdub
07-13-2006, 12:24 AM
Can you share which brand/model you chose?