Electricity is the flow of charge around a circuit carrying energy from the battery (or power supply) to components such as lamps and motors.
Resistor A resistor restricts the flow of charge. Uses include limiting the current passing through an LED, and slowly charging a capacitor in a timing circuit. Some publications use the old resistor symbol
An OR gate can have two or more inputs. The output of an OR gate is true when at least one of its inputs is true.