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Topic: Troubles when using my first transistor (Read 726 times) previous topic - next topic

MarkT

I'd assume its high voltage compared to 5V, it might not be electric-shock high, but I doubt its a logic signal. 

But another issue is interference, a flash discharge involves high voltage high current spike, this could be coupling to the Arduino pin and overloading it.  Opto isolator is a wise precaution, and use twisted pair between it and the Arduino.
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xberg


Opto isolator is a wise precaution, and use twisted pair between it and the Arduino.


Thanks for the reply. What do you mean by twisted pair?

thanks

dc42

If you immediately get a garbled screen when using a 100K resistor from the Arduino pin to base, then I suspect there is something wrong with your wiring or the software. If the flash device really needs just 2mA to trigger it, then 100K should work.

Is the flash unit powered independently from the Arduino, preferably from its own battery and isolated from ground apart from where you connect it to the transistor?
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Grumpy_Mike

You can't measure the current with a meter because the spike is way too fast. You need to use an oscilloscope. If you haven't got one then you need one.
It sounds like voltage is feeding back through the grounds and upsetting the arduino. You need an opto isolated transistor or better still an opto isolated FET.

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