Having trouble with schematic I found online

Thread Starter

snickle

Joined Jan 6, 2021
3
Hello all,

I found a schematic for an ADSR envelope circuit (the third one at https://www.schmitzbits.de/adsr.html), and I tested it in LT SPICE to ensure it works with modified values as I do not have 2M potentiometers. However when I realized the circuit on a breadboard it did not respond when I drove the GATE input with my function generator. I noticed a transient response on my oscilloscope when I tried replacing the 0.01uF film capacitor with different values. However I only captured a short RC charging transient when I set it to single shot mode to see what was happening. Unless I made an oversight with the wiring I am at a loss for what went wrong. Would anyone be able to help me?

I should also note that the pots are in the order Attack, Decay, Sustain, Release, on the bread board.

Thank you very much and please let me know if you need more information.
 

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Thread Starter

snickle

Joined Jan 6, 2021
3
Hello there :)
shorting your breadboard out with the two red jumpers it looks that way but it could be wrong.
Do you mean the long red ones on the power rails? No they are connected plus-plus minus-minus. My "bulk decoupling" capacitor is obscuring them.
 

Alec_t

Joined Sep 17, 2013
12,210
The pins on the pots appear rather wide for the breadboard holes and may have distorted the internal contacts of the breadboard. Are you sure they are making a reliable connection?
 

Thread Starter

snickle

Joined Jan 6, 2021
3
The pins on the pots appear rather wide for the breadboard holes and may have distorted the internal contacts of the breadboard. Are you sure they are making a reliable connection?
The pots are making a good connection! However I did check the circuit again and I noticed I forgot to ground two of the emitters. Duh!

Thanks everyone
 
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