I am trying to build a simple clapper using this schematic. http://www.instructables.com/id/EM92NOB662EP286OAF/
Should pin 4 on the opamp go to 0V or -9V? I do not have the specific model number for the microphone I am using, it is an omnidirectional condenser microphone element from radioshack. The way this is wired, the output of the microphone is always 9V, is this right? Thanks!

 

I am trying to build a simple clapper using this schematic. http://www.instructables.com/id/EM92NOB662EP286OAF/
Should pin 4 on the opamp go to 0V or -9V?

-9v/GND/battery return.

I do not have the specific model number for the microphone I am using, it is an omnidirectional condenser microphone element from radioshack. The way this is wired, the output of the microphone is always 9V, is this right?

If you are measuring between R1 and the microphone, you may very well measure 9v.

I find the schematic very hard to read due to the colors used.

 

-9v/GND/battery return.


If you are measuring between R1 and the microphone, you may very well measure 9v.

I find the schematic very hard to read due to the colors used.

Okay thats what I thought. When I clapped near, spoke into, blew on the microphone there was no change in the voltage, it just stayed at 9V

 

You need an electret microphone, not a condenser microphone.
Radio Shack knows nothing about electronic parts. Their poor quality parts might not work.

An electret mic draws about 0.5mA so its voltage should be abour 4V when powered through 10k ohms from a 9V supply.

 

You need an electret microphone, not a condenser microphone.
Radio Shack knows nothing about electronic parts. Their poor quality parts might not work.

An electret mic draws about 0.5mA so its voltage should be abour 4V when powered through 10k ohms from a 9V supply.

Thank you!

 

Beware! That circuit does not have a protection diode across the relay coil. The parts list is also riddled with typos.

 

There was an older thread about a year ago about the same subject. I think that gentleman may have worked the bugs out, it might be worth searching for it.