Purpose of local Capacitor

Thread Starter

sitheesh

Joined Jan 3, 2023
9
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What is the purpose of this 1uF (i believe it is ceramic caps) Capacitor connector across the DC Rails? There is already a separate Capacitor bank connected across DC Lines? Is there any other purpose of these Capacitor??
 

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Ian0

Joined Aug 7, 2020
9,537
Local decoupling.
Above their self-resonant frequency capacitors cease to be effective at decoupling. 1uF capacitors especially ceramic will have a very high self-resonant frequency, so they can do the high frequency decoupling that the electrolytics can’t.
They are placed closer to the site of switching components on the pcb to negate the effects of the track inductance.
 

Thread Starter

sitheesh

Joined Jan 3, 2023
9
Local decoupling.
Above their self-resonant frequency capacitors cease to be effective at decoupling. 1uF capacitors especially ceramic will have a very high self-resonant frequency, so they can do the high frequency decoupling that the electrolytics can’t.
They are placed closer to the site of switching components on the pcb to negate the effects of the track inductance.
Understood. Thanks for the explanation
 
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