> Can one easily measure the ESR of a capacitor configuration?

Yes.

There are cheap enough meters to do this for you but you can do it 
with an oscilloscope, a square wave source and a resistor if you wish.

Here's an example

        http://octopus.freeyellow.com/99.html

What it does is to rely on the fact that the voltage across a 
capacitor cannot change instantaneously. If you apply a square wave 
voltage through a resistor the initial step in voltage at the 
capacitor will be caused by voltage divider action between the input 
resistor and the ESR. After the leading edge occurs the capacitor will 
start to charge/discharge and you will get a subsequent exponential 
waveform but the initial step allows you to measure the ESR.

Example:        Imagine you have a 10 ohm resistance square wave 
source with a 1 volt peak-peak square wave and a 0.33 ohm ESR.
At the square wave edge the 10 ohms and 0.33 ohms will form a voltage 
divider so you can expect to see the capacitor voltage step by 1V x 
(0.33)/(0.33+10) = 32 mV.

See above article for several practical circuits and a more detailed 
explanation.




        Russell


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