Digital multimeter can form voltmeter, ammeter, ohmmeter, capacitance pen and other basic forms. By changing the measuring selection switch, it is used to measure DC voltage, DC current, AC voltage, AC current, resistance, capacitance, etc. When measuring DC current, the circuit forms a DC ammeter by measuring the conversion of the selector switch.

The sampling resistor r constitutes a current/voltage converter. The measured current I enters from the terminal A and flows out from the terminal B, and there will inevitably be a voltage drop UR on the sampling resistor R, and Ur = IR. Digital meter (200mv digital voltmeter) measures the voltage drop on the sampling resistor, which can indirectly measure the current value. The range can be changed by changing the size of the sampling resistor.

Function of Mathematical Multimeter in Daily Life

1, a positron universal measuring instrument, is called a multimeter because it can measure current, voltage and resistance, and is widely used. It belongs to a multi-purpose electronic measuring tool and can be used in the fields of physics, electrical appliances, electronics and the like.

2. Digital multimeter has automatic recovery protection function. If overload is detected, the multimeter will automatically resume normal operation to avoid the problem of voltage overload.

3. Digital multimeter can distinguish between live wire and neutral wire, and can also find the breakpoint in the circuit without touching the tested line or electrical appliance. It is also relatively simple to use. Connect one end to the power supply, and then set the multimeter to AC20. The black stylus is suspended. Slide it gently with the red stylus to watch the value.