The electric power that comes into our homes is in the form of AC voltage, which means that the voltage and current are constantly changing direction. Most of our electronic, however, require DC voltage to operate, meaning that the devise requires a voltage and current that are always only in one direction. Therefore, we need a way to convert AC voltage into DC voltage. We can do this by using a device called a diode. A diode allows current to flow in the forward direction, but blocks current trying to flow in the backward direction. When current flows in the forward direction, both sides of the diode are at about the same voltage. On the other hand, when the diode blocks current from flowing in the backward direction, the different sides of the diode can be at significantly different voltages. Therefore, by adding just a single diode to the circuit, we have now ensured that the voltage and current across our device will always be only in one direction. However, with this setup, the voltage and current across our device is zero half the time, and this is undesirable. We can fix this problem by using a slightly more clever circuit which uses four diodes instead of just one. Now, the voltage and current across our device are always in only one direction, and they are now no longer zero for half the time. We can even further improve this circuit by adding a capacitor. Capacitors have the ability to store charged particles. When the capacitor is placed in this circuit, the capacitor stores and releases the charged particles so as to try to keep the voltage across the device constant. We have now built an AC to DC converter, which we refer to as a rectifier. Much more information about electric circuits is available in the other videos on this channel.
