Common Methods for Testing Electronic Components with a Multimeter
① Resistance Test SMT resistors are generally printed with resistance‑value marking codes, e.g. 103 (10 kΩ), 102 (1 kΩ). Test with the multimeter resistance range and compare the measured reading against the marked value to judge whether the component is normal.
② Capacitance Test Many digital multimeters are equipped with a capacitance test range. Short‑circuit and discharge the capacitor first, switch to the capacitance test range, then connect the capacitor‑under‑test to the two dedicated capacitance‑measurement terminals, and read the capacitance value. For rough go‑no‑go judgment only, use the resistance or buzzer range. A normal capacitor shows infinite resistance, or resistance rises gradually toward infinity.
③ Diode Test Based on the unidirectional‑conductivity property of diodes, use the diode‑buzzer range. Connect red and black probes arbitrarily. If conduction occurs (a numerical value is displayed), the red probe touches the diode anode and the black probe touches the cathode. When the two probes are reversed, no reading shall be displayed (same as the idle‑test status). Two such measurements confirm that the diode is normal; otherwise it is defective.
④ Inductance Test Some multimeters have an inductance‑test range for measuring inductance, with procedures similar to capacitance measurement. If inductance‑measurement is unavailable, use the buzzer or resistance range only to check for open‑circuit faults. A healthy inductor will trigger the buzzer. Short‑circuit faults of inductors cannot be identified by this method. Special capacitance‑inductance meters or preferably an LCR meter shall be used for accurate testing.
⑤ Transistor Test The internal structure of a transistor is similar to that of a diode, and its judging method is comparable to diode testing.
