Proper Position of Smoothing Cap and Why? Solved

[t1d]

(Assuming the proper small value caps are installed on the Voltage Regulator...) Which is the correct, or better, placement for the Smoothing Cap and why?

1) Mains to Transformer to Bridge Rectifier to Smoothing Cap To Voltage Regulator To Load.

Or

2) Mains to Transformer to Bridge Rectifier To Voltage Regulator to Smoothing Cap To Load.

My guess is #2, because that allows the Smoothing Cap to support the Voltage Regulator, as well.

I look forward to your answers. Thank you for your help. Cheers!

[Swainster]

TLDR: why not both?

Assuming that you are talking about a linear regulator, then one way to look at the situation is to ask these questions;
1) Can a linear regulator do its job when the input is below the require out voltage (plus drop-out voltage)?
2) What does the "un-smoothed" output of a bridge rectifier look like?
These 2 questions lead to #1 being the unavoidable choice, at least for smaller devices. Larger loads may require power factor correction in order to comply with local regulations, which may muddy the waters.

That said, if your design has some kind of particularly 'pulse-like' load, then you would do well to put some local bypassing nearby to that load.

In other words, your #1 option is the usually the best choice, but often there is an element of #2 as well.

[t1d]

TLDR: why not both?

Assuming that you are talking about a linear regulator, then one way to look at the situation is to ask these questions;
1) Can a linear regulator do its job when the input is below the require out voltage (plus drop-out voltage)?
2) What does the "un-smoothed" output of a bridge rectifier look like?
These 2 questions lead to #1 being the unavoidable choice, at least for smaller devices. Larger loads may require power factor correction in order to comply with local regulations, which may muddy the waters.

That said, if your design has some kind of particularly 'pulse-like' load, then you would do well to put some local bypassing nearby to that load.

In other words, your #1 option is the usually the best choice, but often there is an element of #2 as well.

Thanks, Swainster! That's a great answer, information and thinking. Much appreciated!