Check whether the circuit is connected or not with a multimeter
Using the beep range of a digital multimeter can test wire continuity. Two probes touch both ends of the wire separately. If a "beep" sound is heard, the wire is conducting, and no sound indicates that the wire is disconnected. Please refer to the following steps to confirm.
1. Find a digital multimeter and insert the red lead into the "Voltage/Resistance/Diode/On/Off Beep Measurement Terminal" interface of the multimeter, while the black lead is inserted into the "Common Measurement Terminal" interface.
2. Press the power button (i.e. power button) of the multimeter to turn on the device, and press the Hold button to check the switching and holding functions of this button. Rotate the large knob in the middle of the multimeter again to test whether the function conversion is normal.
3. After confirmation, adjust the position of the large knob to the buzzer diode gear.
4. Contact the red pen with the black pen tip, and if it is in the beep mode, you can hear the beep sound. If you do not hear a beep, check if the probe is properly inserted or if the probe is damaged. If the inspection is not a probe issue, it indicates that it is currently in the "diode position". Press the hold key to switch the function to the "beep position".
5. Then, contact the red and black probes of the multimeter with both ends of the wire. If a beep is heard, it can be determined that the wire is conducting, otherwise it is not working.
The measurement of whether the circuit is connected or not with a universal multimeter requires selecting the gear according to the circuit being measured. For example, if the measurement light is not on or the circuit is not connected, a voltage range of AC 250V or above can be used to check whether the power supply is normal. If the voltage indicator of the lighting switch remains unchanged, it can be confirmed that there is a problem with the lighting circuit or light bulb. If there is a change in voltage, it can be determined that the power circuit is faulty; If it is a simple measurement to see if there is a disconnection in the middle of a section of wire, you can use the gear switch shown in the attached picture to turn counterclockwise and then turn it to the second position, that is, to measure the diode and the "on off" position. This is a special gear used by a digital multimeter to measure the on/off of general power wires and the quality of the diode. When the resistance between the measuring probes in this gear is very small (usually below 200 Ω or measuring the forward resistance of the diode), it will directly emit a continuous sound prompt, If the resistance between the probes is large (with a disconnection or when the diode is in reverse connection), it will not sound. If there is a sound discontinuity when shaking the circuit during measurement, it indicates that there is poor contact at the shaking part and the circuit will not be disconnected. Pay attention to using resistance to measure the gear, and the power should be disconnected for testing.
