A car tachometer is a device that is used to determine the number of revolutions of rotating parts of a running engine. The measurement is made per unit of time or according to the speed of the linear movement. A car tachometer helps in choosing the right gear and, as a result, helps to extend the life of the power unit. This means that at the moment when the arrow of the device approaches the red zone, you should immediately switch to a higher gear. An automobile tachometer is often used for adjustment work: at idle and for the purpose of quickly monitoring the speed of rotation of the motor shaft when the car is moving. The principle of operation of such a device is to register pulses coming from sensors. In addition to counting their number, the automobile tachometer records the order in which they arrive, as well as the pauses between counted pulses. At the same time, the calculation itself can be carried out both directly and in reverse, and, if necessary, mixed, that is, in both directions.
As a result, the obtained indicators are transformed into various values, such as seconds, minutes,hours, meters, etc. If necessary, the car tachometer can be reset, thereby resetting all collected values. However, when using such devices, it must be remembered that the accuracy of the measured data is very arbitrary and is approximately 500 rpm, for the best electronic devices it reaches 100 rpm.
Car tachometers come in two varieties: analog and digital.
Digital instruments are made in the form of an electronic display that displays all the calculated information, namely the number of revolutions of the engine and shaft. Such a tachometer is very useful when carrying out adjustment work with the electronic ignition unit of car engines, as well as when setting thresholds in the economizer, etc.
Analogue devices are very popular in the automotive industry. They show the number of revolutions of the power unit by means of an arrow dial. The operation of such a device is carried out according to the electronic principle. This means that the signal from the sensor located on the motor shaft is transmitted to the microcircuit. The latter specifies the movement of the pointer (hand) on a graduated scale. Any analog car instrument and a tachometer for a boat motor work on the same principle. The first is an elementary pulse counter of the engine electrical system. It directly depends on the speed of the crankshaft. Outboard motor tachometers also count electrical impulses, however, they receive "information" directly from the magdino lighting coil, which plays a rolegenerator.
In any car it makes sense to have an additional digital tachometer. It is useful for regulating idle speed and checking the operation of the economizer control unit, as well as the correctness of the standard analog device. This is due to the high measurement accuracy of digital devices. However, when driving a car, it is better to use a pointer device, as it is more visible to the driver.
