You can use your multimeter as an ohmmeter to test the capacitor. 1) Discharge the capacitor by shortening its leads. That is - use a wire and connect the leads of the capacitor together. This will discharge it. 2) put your multimeter in the high ranges 10K-1M 3)CONNECT MULTIMETER TO CAPACITOR LEADS(OBSERVE THE POLARITY IF ELECTROLYTIC). AT SOON AS THE LEADS MAKE CONTACT, THE METER WILL SWING NEAR ZERO. IT WILL THEN MOVE SLOWLY TOWARD INFINITY. FINALLY THE METER WOULD COME TO BE INFINITE OHMS BECAUSE THE CAPACITOR IS BEING CHARGED BY THE BATTERY OF THE MULTIMETER. 4) IF THE CAPACITOR IS BAD, IT WILL GO TO ZERO OHMS AND REMAIN THERE. THIS IS CALLED A SHORTENED CAPACITOR 5) IN THE CASE OF AN OPEN CAPACITOR THERE WILL BE NO OHMMETER INDICATION. 6)SOME CAPACITORS HAVE A LOW DIELECTRIC LEAKAGE. YOU WILL KNOW THIS IF THE OHMMETER COMES TO REST AT A POINT LOWER THAN INFINITE. TEST A KNOWN GOOD CAPACITOR OF THE SAME TYPE TO BE SURE ------------------------------------------------------------------------------- ESR is generally only a problem with large electrolytic caps. Their construction is an aluminium anode with an anodic film 'formed' on it, in contact with an electrolyte which is the cathode. An aluminum 'collector' strip is in contact with the electrolyte to enable current to move in out of the capacitor freely. That aluminium strip is connected to the negative terminal of the cap. The liquid electrolyte has an inherent resistance through which the charge/discharge current must pass and that is its ESR. Any electrolytic will have a certain impedance depending on its capacitance and the frequency it is being used at, and the ESR should be small compared to that. The ratio of ESR to its impedance is its 'power factor'. This feature explains why a small poycarbonate capacitor is often used in parallel with an electrolytic in filter circuits. The tantalum capacitor does not suffer from that problem, and is ideal where a large capacity is required at low and medium frequencies