Anglų skaidrės. Electricity. What is electric current? An electric current is a flow of electric charge. Direct current - DC. Direct current is the unidirectional flow of electric charge. Alternating current - AC. In alternating current the movement of electric charge periodically reverses direction. AC and DC graphs. Diodes. Semiconductor diodes allows. Transistors. Transistors were considered the invention of the twentieth century that changed electronic circuits forever. Resistors. A resistor is. Capacitors. Capacitors store and release electrical charge. Antennas. Antenna is an electrical device which converts electric power into radio waves. Thanks for your attention.