How to Use a Multimeter to Test Electronic Components
Resistance Detection
The most straightforward way to test a resistor is to use the resistance range of a multimeter. Generally, the resistance value is marked on the resistor. Select an appropriate resistance range and connect the red and black test leads to both ends of the resistor. If the reading is close to the marked value, the resistor is normal; otherwise, it is damaged. When measuring high - value resistors, avoid touching both the red and black test leads with your hands. It's not about the risk of electric shock, but to ensure the accuracy of the measurement. It's okay to touch one of the test leads with your hand.
Potentiometer Detection
Normally, a potentiometer has three pins. First, use the resistance range of the multimeter to measure if the resistance between two of the three pins is equal to or close to the marked value of the potentiometer. If there is a large difference, the potentiometer is damaged. If it seems normal, continue to measure these two pins with the multimeter. Then, turn the potentiometer counter - clockwise to a position close to the off state. At this time, the smaller the resistance value, the better. Then, turn it clockwise. If the resistance gradually increases and approaches the marked value when fully turned, the potentiometer is normal.
Fixed Capacitor Detection
In addition to using the appropriate capacitance range of the multimeter to measure the capacitance value, you can also use the resistance range. When measuring, select an appropriate resistance range and connect the two test leads to the two pins of the capacitor respectively. The resistance should be infinite. If the resistance is 0, the capacitor is damaged.
Electrolytic Capacitor Detection
The measurement method for electrolytic capacitors is a bit different from that for fixed capacitors. Of course, you can use the capacitance range for detection, which is well - known. Now, let's talk about the method using the resistance range. First, select an appropriate resistance range. Connect the red and black test leads to the two poles of the capacitor respectively. At this time, the display value will increase from 0 until the overflow symbol "1" appears. If it always shows 0, it means there is a short - circuit inside the capacitor. If it always shows "1", it means there is an open - circuit between the poles of the capacitor, or the selected resistance range may be inappropriate. Note that since electrolytic capacitors have positive and negative poles, do not connect them reversely. Usually, connect the red test lead to the anode of the capacitor (the longer pin) and the black test lead to the cathode (the shorter pin). It's the opposite for a pointer multimeter.
Inductor Detection
Also select the resistance range of the multimeter and connect the test leads to both ends of the inductor. If the measured resistance value is 0, there is a short - circuit inside the inductor. Under normal circumstances, the DC resistance of the measured inductor is directly related to the diameter of the enameled wire used for winding the inductor coil and the number of turns. As long as a resistance value can be measured, the inductor can be considered normal.
Diode Detection
Set the multimeter to the diode detection range. Connect the red test lead to the anode of the diode and the black test lead to the cathode. If the display shows the voltage drop of the diode (usually 0.5V for silicon diodes and 0.2V for germanium diodes), the diode is normal. Then, swap the test leads. If the display shows "1", it is normal; otherwise, the diode is broken down. If the results of both tests are 0 or 1, the diode is damaged.
