A spring dynamometer is a tool for measuring the magnitude of force. First of all, any measurement is a process of comparing a certain physical quantity with a standard (ie, unit). The measurement of force is a process of comparing the effect of a force with that of a known force. If the effect of a force is the same as that of a force of 1 N, the magnitude of the force is 1 N. Secondly, the elongation of the spring is proportional to the magnitude of the applied force. After determining the effect of 1 N force, it is easy to determine the effect of a larger force and a smaller force. In addition, the spring has better stability and can be reused. Therefore, a spring dynamometer can be used to measure the magnitude of the force.

Multimeter, also known as multiplexer, multimeter, three-meter, multimeter, etc., is an indispensable measuring instrument in power electronics and other departments. Generally, it is mainly used to measure voltage, current and resistance. Multimeters are divided into pointer multimeters and digital multimeters according to the display mode. It is a multi-functional and multi-range measuring instrument. Generally, the multimeter can measure DC current, DC voltage, AC current, AC voltage, resistance and audio level, etc., and some can also measure AC current, capacitance, inductance and semiconductor. Some parameters (like β) etc.

Sound level meter is the most basic noise measuring instrument. It is an electronic instrument, but it is different from objective electronic instruments such as voltmeter. When converting an acoustic signal into an electrical signal, it can simulate the time characteristic of the human ear's response speed to the sound wave; the frequency characteristic with different sensitivity to high and low frequencies and the intensity characteristic of changing the frequency characteristic at different loudness. Therefore, the sound level meter is a subjective electronic instrument.

An oscilloscope is a very versatile electronic measuring instrument. It can transform invisible electrical signals into visible images, which is convenient for people to study the changing process of various electrical phenomena. Oscilloscopes use a narrow beam of high-speed electrons to strike a phosphor-coated screen to produce tiny spots of light. Under the action of the measured signal, the electron beam is like the tip of a pen, which can depict the change curve of the instantaneous value of the measured signal on the screen. Using an oscilloscope, you can observe the waveforms of various signal amplitudes changing with time, and you can also use it to test various electrical quantities, such as voltage, current, frequency, phase difference, amplitude modulation, and so on.