The multimeter can measure the quality of the battery and its working principle
Multimeters have a wide range of applications, such as current, resistance, and so on. I believe everyone has also experienced using a multimeter, such as when the refrigerator at home is broken or the circuit is disconnected. Do you know that a multimeter can also measure batteries? Next, let me give you a detailed introduction:
1. Test with a multimeter in the DC range greater than the rated voltage of the battery. For example, test dry batteries at 9V and 1.5V using DC10V and DC2V settings.
2. After selecting the gear according to the rated voltage of the battery, use probes to connect the positive and negative terminals of the battery respectively. When the test voltage is greater than or equal to the rated voltage indicated on the battery label. The battery is intact. When the test voltage is lower than 10% of the rated voltage, the battery can be used on appliances with low discharge depth. For example, quartz clocks, remote controls, and other electrical appliances. When the test voltage is below 20% of the rated value, the battery has no use value.
3. Please be reminded that the voltage of rechargeable batteries is generally 15% -25% lower than that of similar batteries. For example, the voltage of battery # 5 is 1.5V, while rechargeable batteries are generally only 1.2-1.3V. Therefore, it is important to carefully confirm the rated value indicated on the battery label.
When using a multimeter to measure current, it is important to pay attention to one thing. Do not confuse the methods of measuring current and measuring voltage, because many beginners use the same method of measuring current and voltage, directly connecting the probes in parallel into the circuit. If your multimeter is a miscellaneous meter, the fuse will burn out, and the shunt resistor in the current divider will definitely burn out. If it is a digital meter, it is difficult to hang up even the 7106. However, if it is a good multimeter, if the voltage is measured incorrectly using the current divider, this voltage signal will be protected by the current divider protection circuit, which clamps the bidirectional limiting diode at 0.7V to protect the current divider.
We know that the method of measuring voltage is to set the multimeter to voltage mode, then insert the red probe into the V Ω hole and the black probe into the COM hole, and then parallel the red and black probes into the circuit to measure voltage. The current is exactly the opposite. That is to say, if you want to measure current, use the multimeter's current mode and choose the appropriate range. If you don't know the current value, you can choose a larger range to prevent the multimeter from displaying "1" over range. Then insert the red probe into the mA hole or 10A hole, and insert the black probe into the COM hole (the COM hole is called the common terminal for inserting the black probe socket). Then disconnect a part of the circuit and string the red and black probes in series for measurement. If measuring current, it must be measured in series with the wire.
