Re: How do Atom Computer Ignition modules work?

[legendre]

quote debe:

I didn’t test my faulty batch as ive no idea how to do it, but they are fine in another application. I am still waiting for the arrival of 10 x BU931T that ive ordered.

2SD1071 is very easy to ‘proof’ vs. a fake. You only need to do this:

Get a 0-15V @ 1A or better variable PSU. Connect the DUT as follows:

B – to B+ via 10K resistor
C – to B+
E – to GND via 5R 1W (or just straight to GND… but it will be hard to control)

Start to turn up the voltage while watching current though the B (drop across 10K) and E (drop across 5R). By the time B current is 1-2mA the E current will be almost 1A or possibly considerably higher.

Recall that the 2SD1071 is a Darlington NPN with a +minimum+ hfe of 300.. and an hfe of several thousand is more like it, under most conditions. So.. just 1-2mA through the B/E circuit should give you a couple of amps through the C/E circuit, if both are fed in parallel from the same PSU.

If the DUT is fake, you’ll see only 20-50mA though the C/E for a B/E of 1-2mA. Huge difference, you can’t mis-read this one..