What is one characteristic of a tachometer?

A tachometer is a vital instrument found in vehicles, specifically designed to measure the engine speed in revolutions per minute (RPM). This measurement is crucial for understanding how hard the engine is working and helps drivers make informed decisions about gear changes, thereby optimizing performance and efficiency.

Having a clear indication of the engine's RPM allows drivers to avoid over-revving, which can lead to engine damage or inefficiency. Monitoring the tachometer can also assist in understanding when to shift gears, particularly in vehicles with manual transmissions.

In contrast, other choices refer to different gauges: the fuel level is monitored by a fuel gauge, vehicle speed is indicated by a speedometer, and brake temperature is typically assessed by specialized sensors or displays, making them distinct from the functionality of a tachometer.