Astable/scope problem

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Fractal Cat
Posts: 12
Joined: Thu Jun 04, 2015 12:51 am

Astable/scope problem

Post by Fractal Cat » Thu Jun 15, 2017 7:01 pm

Hi,

I have constructed an astable circuit and I want to use the scope to display the voltage across the capacitors. The problem is, when I use
both channels of the scope connecting one channel to each capacitor the astable stops working and both LEDs stay lit. It's ok
when I use just one channel on each capacitor but not with both. Does anyone have any ideas what this might be ?

FC.

David
Posts: 216
Joined: Sun Oct 04, 2015 6:18 pm

Re: Astable/scope problem

Post by David » Fri Jun 16, 2017 5:40 pm

It could be that you are connecting each scope probe leads across each capacitor. The ground leads of each probe will be connected together in the scope, so you may be putting a direct short across some part of the astable circuit. Try connecting the ground lead of each probe to the ground line in the astable. Let us know how you get on - if this doesn't work, please post a circuit diagram!

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