Resistive Sensors Potentiometers

A potentiometer is a variable resistor that is commonly used as a sensor. A potentiometer has three terminals: one for power input, one for a ground and one to provide a variable voltage output. A potentiometer is a mechanical device whose resistance can be varied by the position of the movable contact on a fixed resistor. The movable contact slides across the resistor to vary the resistance and as a result varies the voltage output of the potentiometer. The output becomes higher or lower depending on whether the movable contact is near the resistor's supply end or ground end.

VANE AIR FLOW METER

Potentiometer

^^^ To air Intake chamber

From air cleaner

^^ Measuring plate

The vane type air flow meter on an EFI equipped vehicle is a common location on a Toyota for a sensor that uses a potentiometer. This sensor converts the air flow meter vane opening angle to a voltage and sends it to the Electronic Control Unit (ECU). This signal allows the ECU to determine the volume of air that is entering the engine.

Some models also use a potentiometer as the throttle position sensor. The potentiometer in this case is attached to the throttle shaft of the throttle body. As the shaft is rotated the voltage output of the potentiometer changes. The voltage output of the potentiometer supplies data to the ECU about the throttle opening angle.

THROTTLE POSITION SENSOR

Slider

THROTTLE POSITION SENSOR

Slider

Resistor v----' --(contacts for throttle opening signal)

Resistor v----' --(contacts for throttle opening signal)

Do It Yourself Car Diagnosis

Do It Yourself Car Diagnosis

Don't pay hundreds of dollars to find out what is wrong with your car. This book is dedicated to helping the do it yourself home and independent technician understand and use OBD-II technology to diagnose and repair their own vehicles.

Get My Free Ebook


Responses

  • Jonna
    Are potentiometer on toyota camry engines?
    4 months ago

Post a comment