What tools are there in physics?

Voltmeter is an instrument for measuring voltage, and the symbol of voltmeter-voltmeter is "V". The traditional pointer voltmeter includes a sensitive ammeter with a permanent magnet in it, and a coil composed of wires is connected in series between its two ends. The coil is placed in the magnetic field of the permanent magnet and connected with the pointer of the instrument through the transmission device.

Most voltmeters are divided into two ranges. The voltmeter has three terminals, a negative terminal and two positive terminals. The positive pole of the voltmeter is connected with the positive pole of the circuit and the negative pole is connected with the negative pole of the circuit.

2, ammeter

An ammeter is an instrument used to measure the current in AC and DC circuits. In the circuit diagram, the symbol of ammeter is "circle A". The current value is in the stAndard unit of "an" or "a".

An ammeter is made according to the action of magnetic field force in a magnetic field on a charged conductor. There is a permanent magnet inside the ammeter, which generates a magnetic field between the two poles. In the magnetic field, there is a coil with a hairspring at both ends. Each spring is connected to a terminal of an ammeter, and the spring and the coil are connected through a rotating shaft. There is a pointer at the front end of the rotating shaft relative to the ammeter.

3. Sliding rheostat

Dynamic rheostat is a kind of circuit element, which can change its own resistance, thus playing the role of control circuit. In the circuit analysis, the sliding rheostat can be used as both a constant resistance and a variable resistance. The composition of sliding rheostat generally includes terminals and? Slider, resistance wire, metal bar and porcelain tube.

4, stopwatch

Stopwatch is a commonly used time measuring instrument. It can also be called "mechanical stopwatch" It consists of pause button, clockwork handle, minute hand, etc. It is timed by controlling the rotation of the pointer by using the isochronism of the pendulum.

5, electromagnetic relay

Electromagnetic relay is an electronic control device, which has a control system (also called input loop) and a controlled system (also called output loop). It is usually used in automatic control circuits. In fact, it is an "automatic switch" that uses small current and low voltage to control large current and high voltage. Therefore, it plays the role of automatic adjustment, safety protection and conversion circuit in the circuit.

6, sensitive galvanometer

Sensitive galvanometer is used for students to detect weak current or voltage in DC circuit in experiments or laboratories. It is a highly sensitive magnetoelectric instrument, which can measure the tiny current of10-7 ~10-12a. Such as bridge measurement, thermocouple, electromagnetic induction, photoelectric effect, etc.

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