Jul 02 2009
Our word for the day is ‘Diode’
A diode is an electronic device that has two electrodes arranged in such a way that electrons can flow in only one direction. Because of this ability to control the flow of electrodes, a diode is commonly used as a rectifier, a device that converts alternating current into direct current.
Earlier diodes were vacuum tube diodes, two pieces of metal inside a glass tube. The components inside this tube were a cathode, plate and a heater that surrounded the cathode – as it was heated, it emitted electrons. These electrons would flow from the plate to the cathode if positive and if it was negative charged, there was no flow as the electrons were repelled. Thus, this diode acts as a rectifier and allows the current to flow only in one direction – DC.
New diodes N-type and P-type semiconductors. The two semiconductors are joined together and an electrical current flows from n- to the p- semiconductor, but not the other way – thus, you have the one way current flow for DC. The semiconductor diode operates basically like the vacuum tube, but is more efficient and takes up less space.
