Digital multimeter to test wire continuity
1. The digital multimeter is a powerful tool for electronic measurement. It can be used to measure the continuity of circuits in daily life. Multimeters are divided into digital multimeters and analog multimeters. Generally divided into voltage gear (AC + DC), current gear (AC + DC), and resistance gear. To measure continuity, you need to use the resistance level, which is the simplest function.
2. Let’s take a dental probe as an example. The probe is a plastic handle connected with two metal needles, which is similar to our usual covered wires. In order to determine whether point A and point B are connected, we use Following steps:
1) First ensure that the wiring is correct, the black wire is inserted into the COM socket, and the red wire is inserted into the V (omiga, or diode interface)
2) Place the gear at 200 in the resistance gear, or the "buzzer, diode" gear.
3) Connect the red pen or black pen to the A and B ends to be measured respectively. If A and B are disconnected, the LCD screen will display "1", indicating infinite resistance.
4) Use the same method to measure points A and C to determine whether they are connected. If the wire is connected, there will be a buzzer, and the LCD screen will display a number close to "0", in this case "0.001"; when using the resistance mode, if the wire is connected, it will display A ticking number less than 200. The accuracy of the multimeter is different, and the measurement number is also different, but when it is turned on, it will always be a number close to zero.
The above method can be used in daily life, such as measuring the continuity of wires, the continuity of electrical switches, etc.
3. In daily life, there are other devices that can also be measured by this method, such as headphones, speakers, etc., but their resistance will be slightly larger. The picture below is a schematic diagram of a headset. It can be seen that there are two left and right channels. The essence is that the common terminal and the left and right channel terminals are connected to a coil respectively, which vibrates and makes sound when powered on. The resistance of the coil is generally 30-100 ohms.
4. During actual measurement, you can connect the red and black test leads to the common terminal and the left and right channel ends respectively. Be careful not to touch the lines between the red and black test leads. As can be seen from the example below, the measured resistance between the left channel and the common terminal is 33 ohms, indicating that this channel is normal. You can also use the same method to determine another channel.
5. For pointer multimeters:
1) Correctly connect the red test lead and black test lead
2) Connect the red and black test leads to both ends of the line to be measured
3) If the pointer resistance is close to zero, or relatively small, it means that the lines are connected. If it doesn't move, or the resistance is high, the wire is disconnected.
