How Does an Analog Tachometer Work?

Save

A tachometer is a gauge for indicating the rotational speed of a car’s engine. Traditional mechanical tachometers had an analog needle to indicate engine RPM. Some modern electronic instruments also use an analog needle rather than a digital display.

Mechanical Instruments

  • The operation of a mechanical tachometer is similar to that of a mechanical speedometer. A flexible cable with a rotating shaft connects a moving part in the engine or transmission to the gauge. Inside the instrument, the rotating shaft controls the position of a needle to indicate the engine speed.

Principle of Operation

  • The heart of a mechanical tachometer is an eddy current sensor that contains a movable magnet driven by the rotating input shaft. The spinning magnet in the sensor imparts a force on the indicator needle proportional to the engine speed, while a spring counteracts the sensor force.

Electronic Instruments

  • An electronic tachometer uses a magnetic pickup positioned near a rotating engine part to produce electrical pulses at a frequency proportional to the engine speed. Circuitry in the meter converts the pulse frequency for display of engine RPM using an analog needle or a digital readout.

References

  • Photo Credit tachometer of modern bike image by Oleg Mitiukhin from Fotolia.com
Promoted By Zergnet

Comments

You May Also Like

  • What Does a Tachometer Measure?

    Tachometers, which measure the rpm, or revolutions per minute of a car's engine, provide useful information as to how fast and hard...

  • How to Use a Tachometer on a Watch

    A tachometer, also known as a tachymeter, is an instrument on many sophisticated watches that lets you determine the speed at which...

  • Small Engine Tachometers & Tools

    A tachometer can be in analog or digital format. tachometer of modern bike image by Oleg Mitiukhin from Fotolia.com

  • How to Connect an RPM Meter

    Today most vehicles come stock with rpm gauges, also known as tachometers. This was not always the case, especially back in the...

  • How to Wire a Motorcycle Tachometer

    A tachometer is a device that measures the rotation speed of the engine of your motorcycle, and displays this information to you...

  • Digital vs. Mechanical Bathroom Scales

    Digital and mechanical bathroom scales both serve to monitor weight loss and gain, although digital scales display fractions of a pound for...

  • How Does Auto Insurance Work?

    Auto insurance works by a person paying the insurance company an annual fee to take on the risk of a driver getting...

  • How to Wire a Tachometer

    Every engine spins within the limits of its design. The pistons inside the engine pump the crankshaft to spin. This spinning crankshaft...

Related Searches

Read Article

How to Clean Your Car Headlights

M
Is DIY in your DNA? Become part of our maker community.
Submit Your Work!