Today we will look at the last component in our 3 part series on basic electronic components, the diode.
Diodes only allows electricity to flow through them in a single direction, this is achieved by the diode having a low resistance, ideally zero, in one direction and a high resistance, ideally infinite, in the other direction. This does mean that diodes are polarized (they have 2 terminal, an anode and a cathode) and the direction in which they are placed in a circuit is of great importance.
Diodes are extremely important in converting AC to DC though their use in a bridge-rectifier, but that is a topic for another post.
Diodes usually have 2 markings on them, a band to indicate the side of the cathode and secondly the diode type code (for example 1N4148) this can be used to look up the maximum voltage and current the diode allows.
Here is the schematic symbol used to represent a diode: