Unit 8 How Optomechanical Mouse Works
1. The computer mouse consists of a ball, 2 axles with slotted wheels, some LEDs and phototransistors.
2. When you move the mouse, the ball rolls and turns the axles.
3. These axles have two slotted wheels which cut the path of light from LEDs to phototransistors.
4. The pattern of light to dark is translated into an electrical signal.
5. This signal is then translated into the moves of a cursor on the computer screen.
Unit 9 How Bimetal Thermostat works
1. Bimetal is a strip of two pieces of metal bonded together.
2. When the temperature is low the current flows through the bimetal and heater.
3. When the temperature is high the bimetal bends up and breaks the circuit.
4. When the temperature goes down, the bimetal again closes the circuit and heater is on.
Unit 16 How Photocopiers Work
A document is placed on a platen.
A beam of light scans the document and through a system of mirrors and lenses records the image on a photosensitive drum.
A toner brush puts toner on the drum.
A sheet of paper comes from a paper tray, touches the drum and takes toner from the drum with help of erase lamps.
The heater seals toner on the page.