There are two kinds of electronic signals: analogue and digital. An electronic signal is used to receive or send information between devices. An analogue signal is a continuous current, whereas a digital signal is broken up into separate chunks. An electronic signal is made up of values that represent changes in the voltage of an electrical current as time passes. A voltage is the difference in electrical energy, or ‘potential’, between two points. When demonstrated on a graph, with the voltage value plotted against time passed, an analogue signal is smooth, uniform and continuous.