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classic electronic instruments speedometer sending unit
Composition of electronic speedometer
The electronic speedometer is composed of a speedometer sensor, a signal processing circuit, a speedometer and an odometer. How the electronic speedometer works. The speedometer sensor is installed in the combination instrument and is driven by the transmission through a flexible shaft. When the car is running, it generates a signal proportional to the speed of the car. It consists of a reed switch with one or several pairs of contacts and a rotor. signal processing. The signal processing circuit is composed of electronic circuits such as monostable trigger circuit, constant current circuit, 64 frequency division circuit, power amplifier circuit and power supply voltage stabilization.
become. When the car is running, it will shape and process the pulse signal input by the speed sensor into a current signal, and amplify it to drive the speedometer to indicate the speed; at the same time, it will also convert the pulse signal into a certain frequency through frequency division and power amplification. The pulse signal is used to drive the shaft of the odometer stepper motor to record the mileage of the car.
The speedometer uses a magnetoelectric ammeter as an indicator. When the car runs at different speeds, the signal processing circuit converts the pulse signal input by the speed sensor into a current signal proportional to the speed of the car, deflecting the pointer of the ammeter to indicate the corresponding speed. Odometer. The odometer is composed of a stepping motor, a six-digit decimal counter and an internal transmission gear.
When the car is running, the pulse signal output by the vehicle speed sensor is converted into a pulse signal of a certain frequency through the frequency division and power amplification of the signal processing circuit, which acts on the electromagnetic coil of the stepping motor. The stepper motor converts this pulse signal into an angular displacement signal, so that the motor shaft rotates, and drives the six counting wheels of the odometer decimal counter to rotate in turn, recording the total mileage and one-way mileage of the car. When it is necessary to eliminate the short-range mileage, just press the reset lever once, and the short-range odometer will be reset to zero.c
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