Regulated powersupply, will this work?

[sajti]

to see "how WELL it works" -- you modulate the positive rail going into the regulator with a signal generator (use a blocking capacitor) and look at the output on a 'scope.

This is very nice idea. I made lot of test with my psu. For decoupling I used series connected choke, and coupling capacity. I tested with different types of signal especially with square waves.

Another very good test for load regulation to use mosfet, and resistor connected series as load, and drive the mosfet with square waves. This is very hard test for Your regulator.
As I found some dummy load increase the regulation, and reduce the output impedance.

Sajti