Electronic diodes are an extension of semiconductors. By forming P-Type silicon in a chip of N-Type silicon, electrons will flow through the silicon in one direction only, and this is the principle of the diode. Diodes are usually encased in a small glass cylinder. They have a dark band symbolising the cathode terminal. The opposite terminal is called the anode.
Using Electronic Diodes
Electronic diodes will not conduct until the forward threshold reaches a certain threshold, approx. 0.6 volts. If the current is excessive, the semiconductor chip inside may crack or even melt. If the semiconductor chip melts, then it may start to conduct in both directions resulting in a possible vaporization of the chip.
If a large reverse voltage is applied, then the diode may conduct in the wrong direction and the sudden current surge may lead to the diode’s destruction.
Diode Types
There are many different types of diodes
* Small Signal – These are used to transform low current AC to DC, demodulate radio signals, absorb logic spikes, perform logic, multiply voltage etc.
* Power Rectifier – These are similar to Small Signal diodes, but can handle far larger currents and are often used in power supplies. They have a big metal casing that transfers the heat to a heat sink.
* Zener – The Zener diode has a specific reverse breakdown voltage. They can behave like a voltage sensitive switch and have breakdown voltages of from about 2 – 200 volts.
* Light Emitting Diode
* Photodiode
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