hamming sound noise

Thread Starter

Benengineer

Joined Feb 6, 2016
133
The customer returned the products which has hamming sound with with its circuits. But after we took the Zener Diode and the problem is solved. I am sure which part generates this sounds. Please help me with this question. When I tested TP12 before Zener diode Z1 removed, the output at TP12 was about 5.6V since Z1(SMAZ5V6) stabilizes at 5.6V. But after Z1 was removed, the output at TP12 was 5.9V, then hamming sound was gone. Can you tell me what happends to this circuit? I colored Zener diode Z1 with Red. The input consumer current is about 32.67mA before the Zener diode Z1 was removed. After it was removed, the input consumer current decreased to 27.45mA. So, the hamming sound is gone
Thank you for your help.
upload_2016-2-6_16-16-40.png
 

wayneh

Joined Sep 9, 2010
16,155
It was a joke. You mean "humming". Ham is a cured meat made from pigs, so a "hamming" sound is what a pig makes.
 

Thread Starter

Benengineer

Joined Feb 6, 2016
133
It is working after the Zener diode was removed. But I want to know what caused this noise sounds before it was removed. Is it an avalanch noise sound?

Thanks
 
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