Diodes can be best thought about as stream of water; moving in only one direction. Both, positive and negative, voltages have the capability of transferring through the diode. However, only one type of energy can pass through due to the diode’s one way function. The first types of televisions and radios used to carry diodes that came in the form of tubes. Today, technology has designed smaller and longer lasting diodes called solid state diodes.
Did you know that the LED lights on your keychain actually are a type of diodes? LED lights are actually spelt out light emitting diodes.