The voltmeter is based on the principle that the magnetic effect of the current is larger. The larger the current, the greater the magnetic force generated. The greater the swing of the pointer on the voltmeter, there is a magnet and a wire coil in the voltmeter After passing current, the coil will generate a magnetic field like this
After the coil is energized, it will rotate under the action of the magnet. This is the head part of the ammeter and voltmeter.
The voltmeter can measure various waveform voltages and irregular noise voltage thermocouple detection methods. The linear indication measurement frequency range is 10Hz-10MHz. It has a large mirror indicator and clear reading. DC amplifier output can drive other auxiliary equipment.
A voltmeter is an instrument for measuring voltage. There is a permanent magnet in the sensitive ammeter. A coil made of wire is connected in series between the two terminals of the ammeter. The coil is placed in the magnetic field of the permanent magnet and passed through the drive The device is connected to the pointer of the watch.