[volt-nuts] How to use a Dynamic load

[Fred Schneider]

I do not know if it is of topic but I made a dynamic load, jut for fun as an experiment and i think it is handy for testing caps, finding possible power supply problems, measure RRT from diodes,   Determine unknown transformer specs ect. It was just two matched powerfets, 4 opamps and a few other parts.  I can modulate it internal with sawtooth or squarewave, use a contant resistant or external modulation.
It works great but to be honnest , i have no clue how to interperted the scope pictures I see measuring over the powersupply and over the shunt resistor.

But I read you can test capacitor quality with it, measure Ri of a supply and if I modify it use it to test battery chargers ( not to my intrest) 

I can find only a few schematics, probably use the wrong search terms. And i can not find pictures about how to read the scope pictures and calculate parameters. 
I can find out maybe by studying the pictures and do some math but that is like inventing th wheel again. 

Does some one know some good links to application notes of literature or sites ?

Sorry if this is of topic, but It involves measuring, Volts and I'm a nut ;-)

Fred PA4TIM