Diodes

A diode is a semiconductor that acts like a one-way switch for current, so it allows current to flow in one direction but stops current from flowing in the opposite direction. Diodes are also known as rectifiers because they can change alternating current into pulsating direct current. Diodes have polarity that is determined by an anode (positive) and a cathode (negative) and most diodes allow current to flow when positive voltage is applied to the anode. When a diode allows current to flow it is forward-biased and when it is reverse-biased it becomes an insulator. Credit: fluke.com