Electricity is the flow of charge around a circuit carrying energy from the battery (or power supply) to components such as lamps and motors.
Piezo Transducer A transducer which converts electrical energy to sound
Logic gates process signals which represent true (1, high, +Vs, on) or false (0, low, 0V, off). For more information please see the page on logic gates. There are two sets of symbols: traditional and IEC (International Electrotechnical Commission).