A diode is a semi conductor that allows current to flow in one direction only. It is a type of resistor and acts as a sort of valve. In fact, the earliest diodes to be developed were called valves and not diodes.
When the voltage in an electric current is negative, the current is zero. As voltage is increased, a diode needs an activation voltage to open it up so that it will allow electricity to flow. Once that has happens, the diode behaves just as an ordinary resistor.
The direction in which the diode allows current to flow is marked on a circuit diagram by the direction of the arrow on the diode symbol.
There are many different types of diode that are used in different circuits. Signal diodes channel small currents of 100 milliamps or less. Rectifier diodes can pass larger currents. There are also Light Emitting Diodes (LEDs), which give out light and Zener diodes, which are used to maintain a fixed voltage.
When the voltage in an electric current is negative, the current is zero. As voltage is increased, a diode needs an activation voltage to open it up so that it will allow electricity to flow. Once that has happens, the diode behaves just as an ordinary resistor.
The direction in which the diode allows current to flow is marked on a circuit diagram by the direction of the arrow on the diode symbol.
There are many different types of diode that are used in different circuits. Signal diodes channel small currents of 100 milliamps or less. Rectifier diodes can pass larger currents. There are also Light Emitting Diodes (LEDs), which give out light and Zener diodes, which are used to maintain a fixed voltage.