Fuel Gauges :: essays research papers

the is cut and glue off howstuffworks.com to get an accountIf youre like me, you like to squeeze either last mile you can out of your tank of displace. If you could get 20 miles extra from each tank, that could save you two or three trips to the boast station over the course of a year. The main impediment to stint your mileage is the burn down gauge on your car, which makes you think you have little fuel than you actually do. These devices are notoriously inaccurate, showing empty when on that point are gallons left in the tank and showing full for the freshman 50 miles. In this edition of HowStuffWorks, well learn why our fuel gauges work the way they do. There are two main parts to a fuel gauge the sender, which measures the level of fuel in the tank, and the gauge, which displays that level to the driver. First, lets advert how a typical sender works. The sending unit is located in the fuel tank of the car. It consists of a stray, usually made of foam, connected to a thin, metal rod. The end of the rod is mounted to a shifting ohmic opponent. A resistor is an electrical device that resists the flow of electricity. The more opposite on that point is, the less current will flow. In a fuel tank, the variable resistor consists of a strip of insubordinate material connected on one side to the ground. A wiper connected to the gauge slides along this strip of material, conducting the current from the gauge to the resistor. If the wiper is close to the grounded side of the strip, there is less resistive material in the path of the current, so the resistance is small. If the wiper is at the other end of the strip, there is more resistive material in the currents path, so the resistance is coarse. In the sending unit, the fuel has to drop below a certain level before the float starts to drop.When the float is near the top of the tank, the wiper on the variable resistor rests close to the grounded (negative) side, which means that the resistance is small and a relatively large amount of current passes through the sending unit back to the fuel gauge. As the level in the tank drops, the float sinks, the wiper moves, the resistance increases and the amount of current sent back to the gauge decreases.