Best Capacitor Tester?

[bob91343]

That's why my leakage tester of choice is the GR 1644 megohm bridge.  It can provide any voltage up to 1000 V.

The voltages in between the switch positions are covered by putting a resistance across a pair of terminals, per the manual.

The reading is in megohms, a manual balance of the bridge.  As the capacitor charges, its current tapers off and the resultant megohm reading rises.  Ohm's law tells the leakage.  For instance, 100 megohms at 100 Volts is one microampere of leakage.  That results in a negligible power dissipation so no problem with runaway when in circuit.

Just don't forget to discharge the capacitor when testing is complete; there is a switch position for that.

As a side benefit, you would be hard put to find an ohmmeter capable of the high resistance measurements this bridge can make.  As the company advertisements said 'teraohm territory'.

[mr.fabe]

Hi !

What about the ESR70 model from Peak Electronic Design? Does anyone own one? If so, does it worth the money?

I have one that I use for in-circuit testing.  It's not perfect but it is helpful in identifying bad caps quickly.  The features I enjoy in addition to the ESR are the capacitance reading and capacitor discharge capability.  Good practice is to always discharge the caps prior to testing and this one catches any cap that might not be fully discharged (up to 50VDC).  I also have the MESR 100 v2 that can handle the ESR chores but the short leads are a pain to deal with.  The ESR70 is not the best cap tester but more of a supplemental tool to be used for the quick troubleshooting of capacitors.