Re: [TCML] SCR turn off spike

["Chris Swinson" <list@xxxxxxxxxxxxxxxxxxxxxxxxx>]

Hi Bert..

> Are you connecting a short ground connection from the tip end your 
> oscilloscope probe to the circuit you're measuring? If not, fast the 
> rising/falling logic signals will cause ringing artifacts. Your scope 
> waveform shows an even larger positive spike, and both spikes look like 
> they may simply be measurement artifacts. In any event, SCR's are pretty 
> robust - as long as you don't use excessive gate drive current you should 
> be fine.

I think the ground connection was on the busbar ground, not directly on the 
SCR ground, so it could be that I am reading something which isn't actually 
there...

The spike upwards is in fact the 5V 555 pulse,  if you look at the full page 
http://www.future-technologies.co.uk/IMPULSE/newcoilprog/index2.htm  you can 
see what I mean better.

I will investigate the ground connections later and see if I can get a 
better result!

Cheers,
Chris




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