What is the difference between a speedometer and a tachometer?

[StMargaret]

Speedometer and tachometer differ in that the speedometer's unit of measurement is generally KM/H (kilometers per hour), indicating the current vehicle speed. The tachometer's unit is usually RPM (revolutions per minute), representing the current engine speed. Below are introductions to the speedometer and tachometer: Speedometer: The speedometer is marked with a unit of measurement, typically KM/H (kilometers per hour), while some imported vehicles may use MPH (miles per hour, commonly referred to as "miles"). The numerical value on the speedometer indicates the current vehicle speed. The faster the engine speed, the more pulses the ignition coil generates, resulting in a higher displayed RPM value. Another type of tachometer retrieves pulse signals from the generator, which are then interpreted by the tachometer circuit to display the RPM value. However, due to factors such as generator belt slippage, this value may not be very accurate. Tachometer: The tachometer is marked with a unit of measurement, generally RPM (revolutions per minute), representing the current engine speed. Depending on the type of engine, the tachometer's measurement range is typically from 0 RPM to 7000 RPM. Generally, the scale above 6000 RPM is marked in red, known as the "red zone." It is advisable to avoid prolonged engine operation within the red zone RPM range, as excessively high engine speeds can be harmful to standard engines. Of course, most modern vehicles now employ electronic devices to automatically prevent excessively high RPMs.