How i can check voltage regulator IC 7912 by multimeter?
Answer:
First check to see if you have any shorts between any 2 pins with power off, if so, is problem. If not, then turn on power, black voltmeter probe to common which is the left pin of a TO-220-type package, right pin (facing flat face) of a TO-92-type package, and red to pin next to it, which is the input. The input must be at least about -14V, cannot be more than -35V. If good, move red probe to remaining pin, should measure -12V. If it is less, feel if it is hot (caution-can be hot enough to burn). If it is hot, you may have a shorted output caused by another component. LM79xx and LM78xx-series regulators have built-in thermal and overcurrent protection, and will limit output to a safe (but hot) level if the load is too heavy. See
http://www.national.com/mpf/lm/lm79m12.h...
Well, if you mean a cold check, the best thing is to check the input to ground with your multimeter in 'Diode ' mode, if there is no short cct or open cct (it should show as a diode) that is a good IC. Usually it won't get a problem at the output side.
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