Purpose of power supply filter caps on amps?

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
You have a few premises that need to be modified. The perfect power supply has yet to be built. It's also more important to first deal with the 50/60Hz or 100/120Hz frequency after rectification. Have a look at this pdf, especially noting the waveforms in figures 1, 2, and 5.
Taming those HF transients is probably most commonly done downstream right at the power connections of sensitive components.
 
Administrator
Joined 2007
Paid Member
Thats a very specific circuit with multiple rails. Do you mean why fit 100uf caps when the 70 and 35 volt rails are "perfect" ?

If so its because the rails become "imperfect" after travelling down a few inches of wire and PCB. The 100 uf is a good compromise value to maintain a low impedance.
 
It's sort of like my comment about taming HF at the component. Those rail caps will supply some bypass/reservoir close to the main circuit. This is sometimes done even with battery-powered circuits.

Sorry about the confusion. I figured the "such as this" was some circuit you saw in the forums.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.