i have a simple method of testing ESR, an audio generator with a 50 ohm output impedance, an oscope, and a spare pair of meter leads. connect the scope input to the output of the audio generator, and connect the meter leads also to the audio generator. put the generator on 50 or 100khz, and adjust the scope and audio generator controls to get full deflection on the scope. to get an idea what various values look like, use the meter leads to test some resistors between 1 and 30 ohms, and note the deflection on the scope for each one. use the test leads to test some capacitors, and once you get the hang of it, you will be able to visually determine what caps are good and which ones aren't. the way it works is that the generator, having a 50 ohm output impedance, forming a voltage divider with the caps under test. 100khz assures that almost anyelectrolytic cap will have a reactance of 1.6 ohms or less (usually the smallest common value for electrolytic caps is 1uF)