System Continuity Test

Im running a continuity test on my system. When swtich is off, the multimeter read high resistance of about 75 ohms but no buzz, when switch is on, the tester buzzes and the resistance drops to 11-13 ohms. Why is it doing that? or is there something wrong with the system?

You expect us to know what system, switch, buzz and tester mean without explanation and without a schematic. And then we are supposed to answer a question! Amazing!

First of all, make sure your batteries in the meter are OK.

DVMs I use, stop buzzing at a resistances > 38 ohms.


Buzz test is done by passing a small current through the test point. If the current is below the threshold level then no-buzz. By testing on an active circuit the actual circuit voltage may force sufficient current through the test probes to exceed the minimum threshold level.

You should never do resistance testing on resistors whilst they are actually passing current in an active circuit.

What is the switch connected to?

Tom... :slight_smile: