How to Test Electronic Component
Resistor:
Equipment needed: multimeter
procedure:
1. read the indicated(color-code) value on the resistor body
2. set the multimeter to the OHM-SCALE, the range within but not way below the indicated value.
Good indication:
A resistor is good if its resistance is close to the indicated value. TOlerance should be considered with the ohmmeter.
Defective indication:
1. No resistance reading at all in the OHM scale settings- resistor is open
2. Zero resistance reading at all in hte OHM scale setting- resistor is shorted
Capacitor:
A capacitor fails due to the deterioration of the dielectric material between its plates. Defective capacitor can have a internal shorted terminal, excessive leakage and degradation of capacitance.
Capacitor check can be made with a capacitance meter.
Electrolytic capacitor:
equipment needed: multimeter
procedure:
1. Momentarily short the terminals of the electrolytic capacitor to discharge to discharge it. Be carefull in doing this step to avoid electric shock
2. Set the multimeters to the Rx10 or Rx10k ohm scale.
3. Connect the tester negative probe to the capacitor positive terminal, the positive probe to the negative terminal.
Good indication of electrolytic capacitor:
The meter needle will deflect towards to zero and move back again to the infinite resistance position.
Good indication for ceramic, Mylar or other with capacitance less that 1.0 uF.The meter will not deflect at all.
Defective indication:
1. The meter needle will rest on zero or remain stationary at a point. The electrolytic capacitor is shorted.
2. The meter needle won't deflect at all. The electrolytic capacitor is open.
Potentiometer:
The common defects of three terminal potentiometer and trimmer resistor are opening up of the fixed resistance element and improper contact of the sliding arm to the resistance element.
Eqiupment needed: multimeter
Procedure:
1. Set the multimeter knob to the appropriate resistance range. Example, for a 50k ohm potentiometer, set the multimeter to the x1k or x10k ohm.
2. Place the two tester probes at the exterior terminals these two terminals are the fixed resistance terminal, the needle remains stationary even if the shaft is rotated clockwise or counterclockwise.
3. Rotate the shaft fully clockwise: the resistance reading should gradually fall to zero.
Defective indication:
1. The needle suddenly deflects to infinity and back again to a certain point while the shaft is being rotated. - There is a poor or defective wiper contanct.
2. No resistance reading between exterior terminal. - Open resistive element.
Diode (rectifier and zener)- diode may open up or short.
Eqiupment needed: multimeter(omhmeter)
procedure:
1. Set the multimeter knob to any of the resistance position (x1,x10,or x10k)-depending in the voltage rating.
2. Connect the positive probe to the anode and the(-)com probe to the cathode
Good indication:
the multimeter needle should deflect very little or may not deflect at all.
3. Connect the positive (+) probe to the cathode and the (-)com probe to the anode.
Good indication:
The multimeter needle should deflect considerably towards the zero position. The actual resistance reading is the forward resistance of the diode.
Common defective indication:
1. the multimeter needle does not deflect even when the probes are reverse. the diode is open
2. the multimeter needle deflects at the same or almost the same resistance point (reading)for both procedure 2 and 3.
Light Emitting Diode(LED) same procedure as the diode.
Equipment needed: multimeter
procedure:
1. read the indicated(color-code) value on the resistor body
2. set the multimeter to the OHM-SCALE, the range within but not way below the indicated value.
Good indication:
A resistor is good if its resistance is close to the indicated value. TOlerance should be considered with the ohmmeter.
Defective indication:
1. No resistance reading at all in the OHM scale settings- resistor is open
2. Zero resistance reading at all in hte OHM scale setting- resistor is shorted
Capacitor:
A capacitor fails due to the deterioration of the dielectric material between its plates. Defective capacitor can have a internal shorted terminal, excessive leakage and degradation of capacitance.
Capacitor check can be made with a capacitance meter.
Electrolytic capacitor:
equipment needed: multimeter
procedure:
1. Momentarily short the terminals of the electrolytic capacitor to discharge to discharge it. Be carefull in doing this step to avoid electric shock
2. Set the multimeters to the Rx10 or Rx10k ohm scale.
3. Connect the tester negative probe to the capacitor positive terminal, the positive probe to the negative terminal.
Good indication of electrolytic capacitor:
The meter needle will deflect towards to zero and move back again to the infinite resistance position.
Good indication for ceramic, Mylar or other with capacitance less that 1.0 uF.The meter will not deflect at all.
Defective indication:
1. The meter needle will rest on zero or remain stationary at a point. The electrolytic capacitor is shorted.
2. The meter needle won't deflect at all. The electrolytic capacitor is open.
Potentiometer:
The common defects of three terminal potentiometer and trimmer resistor are opening up of the fixed resistance element and improper contact of the sliding arm to the resistance element.
Eqiupment needed: multimeter
Procedure:
1. Set the multimeter knob to the appropriate resistance range. Example, for a 50k ohm potentiometer, set the multimeter to the x1k or x10k ohm.
2. Place the two tester probes at the exterior terminals these two terminals are the fixed resistance terminal, the needle remains stationary even if the shaft is rotated clockwise or counterclockwise.
3. Rotate the shaft fully clockwise: the resistance reading should gradually fall to zero.
Defective indication:
1. The needle suddenly deflects to infinity and back again to a certain point while the shaft is being rotated. - There is a poor or defective wiper contanct.
2. No resistance reading between exterior terminal. - Open resistive element.
Diode (rectifier and zener)- diode may open up or short.
Eqiupment needed: multimeter(omhmeter)
procedure:
1. Set the multimeter knob to any of the resistance position (x1,x10,or x10k)-depending in the voltage rating.
2. Connect the positive probe to the anode and the(-)com probe to the cathode
Good indication:
the multimeter needle should deflect very little or may not deflect at all.
3. Connect the positive (+) probe to the cathode and the (-)com probe to the anode.
Good indication:
The multimeter needle should deflect considerably towards the zero position. The actual resistance reading is the forward resistance of the diode.
Common defective indication:
1. the multimeter needle does not deflect even when the probes are reverse. the diode is open
2. the multimeter needle deflects at the same or almost the same resistance point (reading)for both procedure 2 and 3.
Light Emitting Diode(LED) same procedure as the diode.
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