Car windscreen wipers - Activity

What does the model show?

A practical application of an AND gate controlling car windscreen wipers is shown.


Windscreen wipers

Demonstration Instructions

Circuit notes:

  • The circuit simulates car windscreen wipers
  • One switch simulates the car ignition and the other the wiper switch
  • The AND gate produces an output only when both of its inputs are high
  • The motor simulates the wiper drive motor
  • The switches are stable either on or off (high or low).
  1. Close both switches by left clicking each in turn with the mouse.
  2. Point out that the motor is rotating and this simulates the windscreen wipers.
  3. Open one switch and show that the motor stops.
  4. Repeat this for the other switch and then for both switches.
  5. Explain the motor only comes on when both switches - the ignition and the wiper switch - are high simultaneously.