Input, process and output devices
There are a range of different sensorA device that measures a physical quantity and converts it into a signal to be read and interpreted., control devices Items such as switches that control the supply of electricity. and output deviceA device that turns an electronic signal back into a 'real-world' signal, such as light or sound. that can be used together or separately depending on what function the product needs to achieve. These components are split into the three categories:
- inputs
- processes
- outputs
Some examples include:
Input
| Sensor | Function | Use |
| Light-dependent resistor (LDR) | The resistance changes as the light level changes, and the change in resistance can be used as an input | Solar garden lights and street lighting |
| Thermistor | The resistance changes as the temperature changes, and the change in resistance can be used as an input | Fridges, central heating systems and freezers to maintain temperatures |
| Piezoelectric sensor | Can change mechanical motion or force into electrical energy - it can produce an electrical pulse from pressure, such as by hitting it | Igniting lighters and in microphones (where soundwaves create pressure that makes the electrical pulse) |
| Sensor | Light-dependent resistor (LDR) |
|---|---|
| Function | The resistance changes as the light level changes, and the change in resistance can be used as an input |
| Use | Solar garden lights and street lighting |
| Sensor | Thermistor |
|---|---|
| Function | The resistance changes as the temperature changes, and the change in resistance can be used as an input |
| Use | Fridges, central heating systems and freezers to maintain temperatures |
| Sensor | Piezoelectric sensor |
|---|---|
| Function | Can change mechanical motion or force into electrical energy - it can produce an electrical pulse from pressure, such as by hitting it |
| Use | Igniting lighters and in microphones (where soundwaves create pressure that makes the electrical pulse) |
Process
| Control device | Function | Used |
| Switch | A switch can either allow or prevent electrical power from flowing round a circuit | Any device that needs power to be turned on and off |
| Resistor | To limit the flow of current - they are made to restrict current flow in varying degrees (resistance) | All electrical products - it helps control the flow of current and protects delicate components from being overloaded |
| Programmable components | A programmable component is a chip that can be programmed to make decisions based on an input | Most modern electrical products - washing machines are programmed to work when the drum door is shut and the on/off button is pressed |
| Control device | Switch |
|---|---|
| Function | A switch can either allow or prevent electrical power from flowing round a circuit |
| Used | Any device that needs power to be turned on and off |
| Control device | Resistor |
|---|---|
| Function | To limit the flow of current - they are made to restrict current flow in varying degrees (resistance) |
| Used | All electrical products - it helps control the flow of current and protects delicate components from being overloaded |
| Control device | Programmable components |
|---|---|
| Function | A programmable component is a chip that can be programmed to make decisions based on an input |
| Used | Most modern electrical products - washing machines are programmed to work when the drum door is shut and the on/off button is pressed |
Output
| Output device | Function | Use |
| Loudspeaker | Uses pulses of electricity to move an electromagnet that vibrates to create sound | Speakers, headphones and radios |
| Motor | Converts power into rotary motion that can turn a spindle linked to gears or wheels to make them move | Cars and trains |
| Light-emitting diode (LED) | A long-lasting, low-power light | Torches, lamps and power indicators |
| Output device | Loudspeaker |
|---|---|
| Function | Uses pulses of electricity to move an electromagnet that vibrates to create sound |
| Use | Speakers, headphones and radios |
| Output device | Motor |
|---|---|
| Function | Converts power into rotary motion that can turn a spindle linked to gears or wheels to make them move |
| Use | Cars and trains |
| Output device | Light-emitting diode (LED) |
|---|---|
| Function | A long-lasting, low-power light |
| Use | Torches, lamps and power indicators |
