Switching Power Supply 0-10A 0-25V

Sceadwian

Banned

• Apr 5, 2009

• #21

What do you think a filter capacitor does? Just sit there in the circuit to look good? =-) They absorb energy and feed it to the circuit during the low portion of the AC cycle. If you have a lot of ripple or it's a single phase AC mains supply there's quiet a bit of current going through the filter caps.

 

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bbjk

New Member

• Apr 5, 2009

• #22

yeah i knew that... but where is the current actually lost? the capactior stores charge during the low part of the AC then feeds it back during the high part...

 

Sceadwian

Banned

• Apr 5, 2009

• #23

Capacitors aren't perfect. They have an ESR rating, they heat like any physical object does when current passes through it.

 

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bbjk

New Member

• Apr 5, 2009

• #24

also, smanches, i had a look at pwm using a 555 and i understand it somewhat... but its hard to see exactly how it is varried in the curcuit... something to do with the op-amp?

 

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bbjk

New Member

• Apr 5, 2009

• #25

Sceadwian said:

Capacitors aren't perfect. They have an ESR rating, they heat like any physical object does when current passes through it.

Click to expand...

ok... thx, still seems like a lot though...