What does the engine tachometer mean?

[OMadelyn]

Car tachometer indicates the engine speed, which means the number of revolutions per minute (RPM) of the engine. The tachometer is usually located on the instrument panel, symmetrically placed alongside the speedometer. The data on the car tachometer represents how many revolutions the engine makes per minute. Regarding the working principle of the car tachometer: The tachometer receives digital pulse signals (emitted by sensors), processes them, and directly reads them into the CPU's counting port. The software then calculates the speed and the corresponding position of the pointer. Through the CPU's control port, the signal is amplified to drive the stepper motor to rotate in both positive and negative directions, indicating the corresponding speed value (the pointer is directly mounted on the rotating shaft of the stepper motor). Each step of the stepper motor is only 1/3 degree. All car engines have an RPM at which they output maximum torque. When the transmission is in a certain gear (except the highest gear), once the engine speed reaches the RPM for maximum torque output, the vehicle speed will definitely reach the maximum speed that this gear can handle. At this point, it is necessary to shift gears.