Contents What is Electricity Conductors, Insulators    and semiconductors   Amps, Volts and Ohm's   Current Voltage   Which way does current flow?   Resistance   Ohm's Law   Using a Systems Approach   Types of Signal   Analogue Input sensors   Providing a reference signal   Potential Divider Formula   Light Sensors   Temperature Sensors   Sound Sensors   Position sensors Pressure Sensors   Magnetic sensor   Output Transducers   Motors - DC and Stepping   Solenoids Loudspeakers and Buzzers Lamps and LED's   Relays Meters and Oscilloscopes Analogue Signal Processing Amplifying Analogue signals Common Emitter Bipolar transistor Common Collector Bipolar transistor   The Darlington Pair FET's and MOSFET's Analogue to Digital   Schmitt Trigger Timing Circuits What is a Capacitor ? Types of Capacitor How a Capacitor Works Charging and        Discharging a       Capacitor Using Capacitors in Time Delays 555 Timing Circuits Monostable Operation   Astable Operation Switches in Control Arrangement of Contacts   Using switches Motor Control Switch Logic Digital Signals Logic Functions Combining Logic Gates Building a Latch A latch from Logic Gates A Monostable built with logic gates Bistables Flip-Flops Number Systems Counting Circuits Decoder Circuits