The following schematic shows a typical circuit diagram of the Mass Air Flow (MAF) Sensor system. The mass air flow sensors converts the amount of air drawn into the engine into a voltage signal. The primary components of the MAF sensor are thermistor, a platinum hot wire, and an electronic control circuit. The thermistor measures the temperature of the incoming air.
The hot wire is maintained at a constant temperature in relation to the thermistor by the electronic control circuit. An increase in air flow will cause the hot wire to lose heat faster and the electronic control circuitry will compensate by sending more current through the wire.