Electric measuring tool of measuring instrument

Working principle of electric measuring instrument

The measured change (linear displacement or angular displacement) is converted into an electrical signal, which is displayed or controlled by an actuator after being amplified by the circuit, thus completing the predetermined measurement purpose.

Basic components of electric measuring instruments

The electric measuring instrument consists of three parts: sensor, measuring circuit and display actuator. The sensor, also known as the electric probe, first directly contacts the measured object, feels the change of the measured parameter, and converts this change into the change of the electric parameter in the sensor. Electrical parameters should include circuit parameters (inductance and capacitance) and electrical parameters (voltage and current). Because the sensor realizes the first conversion of the measured signal, it is also called a primary instrument. The task of the measuring circuit is to amplify the weak electrical signal output by the sensor into a strong electrical signal, and then drive the indicating (or digital display) device or actuator after transformation according to people's needs. The measuring circuit generally consists of an amplifier circuit, an arithmetic circuit, an indication (display) or a control circuit, and also includes a carrier signal source (oscillator) and a DC regulated power supply controlled by a transistor. The display actuator can be an electric meter, a signal lamp, a digital display device, an automatic recorder, an automatic printer or a mechanism for automatically grouping workpieces or controlling the actions of a machine tool. Measuring circuit and display actuator realize the reconversion of sensor output signal, so it is also called secondary instrument.

Domestic and foreign electric meter manufacturers

Well-known brands of electric measuring instruments include domestic Oriental measuring instruments and Central Plains measuring instruments, and foreign famous brands include Mabos, Tokyo Precision, German mahr and Swedish TESA.