August 15, 2007 AT 10:48 pm

First sketch: Arduino beta tester

I installed Arduino IDE 009 since I figured I should learn this stuff if I’m going to sell Arduino’s (and clones)

My project today was to build a simple NPN Hfe (Beta) meter to do some tests on the now ultra-rare 2sc2291 matched pairs. My multimeter has one but I wanted to make sure I was testing with the same setup as the one in the datasheet, with a Vce of about 6V and Ic = 1mA. The results are in the x0xd0x wiki

This is the breadboard circuit I used:

its similar to the one described on the x0xb0x page, but with the op amp swapped around for NPN’s

The sketch is rather small, I just take the two analog measurements, do a bit of math and spit out the calculated beta. I checked this against my meter and it matched up for lower betas (although not for higher ones, which may mean I’ve got current leaking into the opamp)


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