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Cannot get this circuit to work

bigkim100

Apr 17, 2013
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Ok, here is a Squelch Circuit that I have built, but cannot get it to work (Illustration 1)
the input toU1pins 2 and 3 seem to be backwards compared to the standard schematics, (see illustration2) but I dont know. If the schematic seems ok, them I will proceed with rebuilding it.
Im mostly looking to see what people think of the schematicc, and if any problems seem to be in it.
The audio driving it is from a standard transistor radio.
Any ideas?
Thanks in advance.
 

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kellys_eye

Jun 25, 2010
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Probably a result of some construction error..... show your layout etc.
 

Martaine2005

May 12, 2015
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Is this on a breadboard?, connections are a major hurdle sometimes.

Martin
 

bigkim100

Apr 17, 2013
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Its on Perf, and I usually make working circuits, but hell, there is always room for error.
 

Delta Prime

Jul 29, 2020
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Ok, here is a Squelch Circuit that I have built,
Get rid of the 741 & "86" the 386. talk about dinosaurs. Make it complete and throw 555 in there. I don't know what that is but it's not a squelch circuit.
A squelch circuit is to mute or silence the audio output of the receiver in the absence of the desired radio signal.
A"open" receiver may pick up another signal or background radio "noise."
Typically, this is heard as "white" noise & is often much much louder than the audio signal from the desired source.
The traditional squelch circuit is an audio switch controlled by the radio signal level using a fixed
or manually adjustable threshold (level).
With that said what is your intended use for the circuit what would you like it to do?
 
Last edited:

kellys_eye

Jun 25, 2010
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Get rid of the 741 & "86" the 386. talk about dinosaurs. Make it complete and throw 555 in there. I don't know what that is but it's not a squelch circuit.

There's nothing wrong with the 741 or the 386 when used in this way. A 555 can't be used for a squelch application since it is a timer..... and the circuit shown IS a squelch.

The 741 is simply configured as an AC amplifier followed by rectification and switching - switching the power to the 386 giving an, effectively, mute operation. The 386 is used in a 'classic' configuration and shown correctly.
 
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