Is the fuel gauge an ammeter or a voltmeter?
2 Answers
The fuel gauge in a car is an ammeter, not a voltmeter. The movement of the float changes the value of R, which affects the current. Introduction to the dashboard: The trip computer display, also known as the multi-information display, presents part of the trip computer's data on a screen. It typically shows driving information and multimedia information. Information displayed on the dashboard: Most trip computers display data such as average fuel consumption, instantaneous fuel consumption, outside temperature, average speed, driving time, and single-trip mileage, allowing the driver to stay informed about the vehicle's status.
Strictly speaking, the fuel gauge doesn't belong to traditional ammeters or voltmeters. After driving for over a decade, I've found its working principle quite unique. A fuel float is connected to a sliding rheostat, which changes resistance value as the fuel level fluctuates. Essentially, the fuel indicator is an ammeter - when current flows through the instrument coil, the float's resistance variation alters the current passing through the coil, causing the needle to move. So while it measures current, what directly correlates with fuel level is the resistance change. Occasionally during cold starts, the fuel gauge might jump erratically, likely due to unstable current from poor wiring contact. When older cars' fuel gauges suddenly drop to zero, it's often because the float gets stuck in the tank. Additionally, irregularly shaped fuel tanks can cause slight reading deviations, like the common phenomenon where the first half tank depletes slower than the second half.
