Electrical Systems

• input, process + output
• a signal passes from one block to the next which changes the signal in some way
• easiest example is of a bike (a mechanical system)
  • input = pedals
  • process = chain + sprockets
  • output = rear wheel
• electrical systems use a circuit
• insulators (eg PVA) don't let electricity through  = used to coat outside of the wires
• portable = batteries used
• non-portable = mains used
• you can use rechargeable batteries = more expensive but maybe not in long run

Input devices

• swiches; toggle, push + slide
• Light-dependent resistors (LDRs) sense changes in light levels
• Thermistors sense changes in temperature

Process devices

• egs. timers, amplifiers + pluse generators

Output devices

• Lights; bulbs + LEDs
• Buzzers
• Motors

E.g. you press a Switch which starts a Timer which sets off a Buzzer