Let's Talk About Capacitor Ripple Current

[Inquisitive]

Hi Everyone,

So, I was looking at Panasonic Aluminum Electrolytic Capacitors they give a ripple current specification. Can somebody enlighten me? These are all 100uF caps.

Here are three samples:

Panasonic ECA-1EHG101 Ripple Current: 130 mA
Panasonic EEU-EB1E101S Ripple Current: 95 mA
Panasonic EEU-FM1E101 Ripple Current: 455 mA

If I'm looking to smooth a 9VDC power supply for MCU's which is the better choice? Can you explain how to use these specs to my advantage.

 

[Nigel Goodwin]

Bigger than a 100uF would be better (assuming it's the reservoir capacitor)

Apart from that, any of the three would be perfectly fine, it's not a concern for a simple application like this.

 

[ronsimpson]

If I'm looking to smooth a 9VDC power supply for MCU's which is the better choice?

You did not say if the supply is switching (PWM) or just a 60hz transformer and diodes.
You did not say what the load current is.
Often the current spec. has numbers for 60hz and different numbers for 100khz.

 

[MikeMl]

Also affected by transformer secondary voltage, the dropout voltage of the regulator

 

[Inquisitive]

You did not say if the supply is switching (PWM) or just a 60hz transformer and diodes.
You did not say what the load current is.
Often the current spec. has numbers for 60hz and different numbers for 100khz.

Sorry about that. Using a wallwart 120VAC 60Hz to 12VDC 200mA hooking to a microcontroller circuit

 

[Nigel Goodwin]

Sorry about that. Using a wallwart 120VAC 60Hz to 12VDC 200mA hooking to a microcontroller circuit

As it's DC even less reason to pay any attention to ripple current

 

[crutschow]

The ripple current spec is just the maximum current the capacitor can tolerate without overheating.