A rheostat, or variable resistor, is what is used to vary the intensity of lighting in such things as car instrument panels.
A rheostat consists of a length of coiled resistance wire,one end of which is connected to the live feed wire. The other end of the rheostat wire is not connected to anything.
A second wire runs from the rheostat to the load via a movable element called a wiper.
This wiper, a slider, skims the surface of the resistance wire. The closer the wiper is to the battery feed wire end of the resistance wire, the more current it is able to draw. The further the wiper is from the battery feed wire, the smaller the amount of current it is able to draw because there is more resistance wire for the current to overcome. The sliding motion allows precise amounts of current to reach the load.
However, rheostats can't normally handle the level of current required for heater blowers. Such high current circuits as heater blowers which require variable amounts of current are fitted with single pole, multiple-throw slide switch.
A rheostat consists of a length of coiled resistance wire,one end of which is connected to the live feed wire. The other end of the rheostat wire is not connected to anything.
A second wire runs from the rheostat to the load via a movable element called a wiper.
This wiper, a slider, skims the surface of the resistance wire. The closer the wiper is to the battery feed wire end of the resistance wire, the more current it is able to draw. The further the wiper is from the battery feed wire, the smaller the amount of current it is able to draw because there is more resistance wire for the current to overcome. The sliding motion allows precise amounts of current to reach the load.
However, rheostats can't normally handle the level of current required for heater blowers. Such high current circuits as heater blowers which require variable amounts of current are fitted with single pole, multiple-throw slide switch.