Hi gang:

When would it not be appropriate to use low ESR caps in a power supply filter?

Aram

 

Here is a graph of the output capacitor for a LDO voltage regulator. If the "R" is too low the regulator will be unstable.

 

Mr. Simpson, would this apply to 78xx's? Particularly a 7812?

 

Mr. Simpson, would this apply to 78xx's? Particularly a 7812?

Here is a graph of the output capacitor for a LDO voltage regulator. If the "R" is too low the regulator will be unstable.
View attachment 197768

And... when you say "unstable" do you mean a jittery performance in holding the voltage at a regulated point, or other issues? If so what kind of issues would instability cause?

 

You need to consult the data sheet for the particular regulator you're using; there is no universal "correct" answer.

In the "unstable" regions, the regulator either oscillates or shows poor transient response in the presence of changing load current.

 

Here is a graph of the output capacitor for a LDO voltage regulator. If the "R" is too low the regulator will be unstable.
View attachment 197768

Do you happen to have the full document on this?

 

Hi gang:

When would it not be appropriate to use low ESR caps in a power supply filter?

Aram

https://electronics.stackexchange.com/questions/109385/when-should-i-use-a-low-esr-capacitor