2. Input, process and output When considering electronic systems we can say that it is made up of 3 main parts.When considering electronic systems we can say that it is made up of 3 main parts. InputInput ProcessProcess OutputOutput

3. Definitions Data has to flow into the system in some form.Data has to flow into the system in some form. INPUT is the data flowing into the system from outsideINPUT is the data flowing into the system from outside The next stage in the information flow is the input data being manipulated in some way. PROCESSING is the action of manipulating the input into a more useful form.

4. Definitions The final stage in the information flow is normally to present the information.The final stage in the information flow is normally to present the information. Output is the information flowing out of the system.Output is the information flowing out of the system. Example Calculator Input – keypad Process – Microprocessor Output – Display

5. Definition A transducer is a device which converts an input signal into an electrical signal or an electrical signal into an output signal.A transducer is a device which converts an input signal into an electrical signal or an electrical signal into an output signal. Examples – a microphone converts sound energy into electrical energy and a loudspeaker converts electrical energy into sound energy.Examples – a microphone converts sound energy into electrical energy and a loudspeaker converts electrical energy into sound energy.

6. Analogue and Digital Signals An analogue signal can have any value in the range.An analogue signal can have any value in the range. A digital signal appears as a square wave where values are either on or off, 1 or 0, high or low.

7. Input Devices Microphone – changes sound energy into electrical energy. It is an analogue device.Microphone – changes sound energy into electrical energy. It is an analogue device. Thermocouple – consists of two wires twisted together to form a junction. When the junction is heated a small voltage appears. Thermocouples change heat to electrical energy. Heat to electrical energy. Analogue device.

8. Input Devices Solar Cell – semiconductor which produces a voltage when light falls on it.Solar Cell – semiconductor which produces a voltage when light falls on it. Light to electrical energy.Light to electrical energy. Analogue device.Analogue device. Thermistor – device which changes its resistance depending on the temperature. Used as a temperature control device. Analogue device.

9. Input Devices Light Dependent Resistor (LDR) Device which lowers its resistance as temperature increases. Device which lowers its resistance as temperature increases. Switch – Used to open/close a circuit to stop/start the flow of current.

10. Input Devices Voltage DividerVoltage DividerCapacitor