Question about CGS gate to trigger [SOLVED]

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batchas
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Question about CGS gate to trigger [SOLVED]

Post by batchas » Mon Jun 29, 2020 5:11 am

If I emulate quickly the CGS gate to trigger circuit. I see a negative signal at the output.
Is it the emulation that does something weird (maybe because of the opAmp as I can't define it as LM358 or LM324) or(more likely) me doing something wrong?


EDIT: added "EDIT: solved." in this post and forgot to add it in the title. Then edited again to change the title :)
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Last edited by batchas on Tue Jun 30, 2020 12:23 am, edited 2 times in total.
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batchas
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Re: Question about CGS gate to trigger

Post by batchas » Mon Jun 29, 2020 5:11 am

Ooops. Double post.
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Chaotic
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Re: Question about CGS gate to trigger

Post by Chaotic » Mon Jun 29, 2020 5:45 am

You have drawn it wrong

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dot matrix madness
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Re: Question about CGS gate to trigger

Post by dot matrix madness » Mon Jun 29, 2020 6:47 am

The resistors around the positive and negative input are drawn wrong. The kind of OpAmp doesn't play a role
in the simulation. However, in real life the "slow" LM358 is preferred over faster one, because it doesn't
get into self oscillation.
Licenced to solder since 1993

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Re: Question about CGS gate to trigger

Post by batchas » Mon Jun 29, 2020 1:13 pm

Awesome. Thank for your help.

I'll look at the resistors again tomorrow then, cause right now I don't see my error. Need to take some distance!
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Repeater
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Re: Question about CGS gate to trigger

Post by Repeater » Mon Jun 29, 2020 2:18 pm

Another thing to check once you've fixed the connection of that voltage divider is how you've powered your opamp. Ken's circuit is single supply with a LM358 and the negative rail is not used. Can't speak to your simulation, but in real life a TL072 for example will not give the same performance as a LM358 in this application.

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batchas
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Re: Question about CGS gate to trigger

Post by batchas » Tue Jun 30, 2020 12:22 am

Just woke up and had a look at what I did. OBVIOUS. HA!
Yesterday I was incapable of seeing it, though it was completely wrong!!! I even forgot the 100k resistor.
Scary...

Anyway, as usual always good to have a break when you don't see see what is wrong, instead of insisting.
It's so simple, I should have draw it on paper and breadboard it instead. Way quicker and keeps me away from the monitor which does not do me good at all.

Again thanx a lot for all answers! Very helpful :tu: :tu: :tu:
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