How To Test Basic Electronic Components

How to test resistors?

Read the indicated color code value then select the OHM-scale within but not way below the indicated value. A resistor is good if its resistance is close to the indicated. Tolerance should be considered with the ohmmeter reading. While, no resistance reading at all on the ohmmeter scale settings, the resistor is open. A zero resistance reading on all ohmmeter scale settings, resistor is shorted.

How to test capacitors?

In most cases, a capacitor fails due to the deterioration of the dielectric material between its plate. Defective capacitors can have an internal shorted terminals, excessive leakage and degradation of

capacitance meter. Momentarily, short the terminal of the electrolytic capacitor to discharge it.

To test a capacitor, set the multi-tester to Rx 10 or Rx1K scale. Connect the tester negative probe to the capacitor positive terminal, the positive probe to the negative terminal. A good indication for electrolytic capacitor shows the meter needle deflecting towards zero and moves back again to infinite resistance position. For ceramic, Mylar and other capacitor with a capacitance with less than 1.0 uF, the meter will not deflect at all. A defective indication for an electrolytic capacitor shows that the meter will rest on zero and remain stationary at a point which is an indication that the capacitor is shorted.

How to test diodes?

Set the multi-tester knob to any of the resistance position (x1, x10, x1K or 10K ohm ). Connect the positive probe to the anode and the negative probe to the cathode. Then connect the positive probe to

the cathode and the negative probe to the anode of the diode. A good indication in the first procedure will show the meter deflected very little or may not deflect at all. And in the second procedure, the meter will deflect towards zero. The actual resistance reading is the forward resistance of the diode. A defective indication shows that the meter won't deflect at all even when the probes are reversed. Or the meter deflects at the same time or almost the same resistance reading for both steps.

How to test transistors?

Bipolar transistors are usually checked out of a circuit by means of an ohmmeter. When it is desired to check for the resistance across the transistor emitter and collector, NPN or PNP, ohmmeter probes may be connected either way. A good transistor will show above a reading above 1000 ohm.

How to determine if it is NPN or PNP transistor?

To determine the correct terminal of the transistors, set the range selector to x 1 or 10 ohm. Connect the positive probe to the emitter and the negative probe to the base of the transistor. Note the reading interchange the connection of the probes to the leads of the transistor.

note: originally posted at Exposeknowledge.com under the same author.
 



Article Written By joeldgreat

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Last updated on 18-07-2016 130 0

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