Sound noise in the driving circiut

[karthickb3e]

hi all,,

In my driving circuit i use the capacitor across the circuit... the circuit is limited to 200mA to load... the switching frequency is 4khz....

i used the electrolatic capacitor of 22uF... which occupies more space....

the problem is when i replace the capacitor with eq. of 22uf ceramic type (to reduce the space) , the circiut becomes more noisy(sound).................

please give solutions to find the problem...

 

[rfredel]

Hello B. Karthick,

please show your circuit, then you get quickly help.

Regards

Rainer

 

[chuckey]

The only components that have audible noise are ferrite and other magnetic components, as the changing flux actually changes the shape of the item which then acts as a little loudspeaker. So your two capacitors are changing the currents around the circuit to change the magnetic effect and hence the noise. a 22MF CERAMIC capacitor?
Frank

 

[FvM]

High er ceramic capacitors are known to have considerable piezoelectric effect. You may want to use tantal caps if the effect matters.

See e.g. https://www.edaboard.com/threads/192336/