1, diode composition:
Diodes are composed of two kinds of semiconductor materials, one is a P-type semiconductor doped with a small amount of trivalent impurities, such as boron (b) or gallium (ga); The other is an N-type semiconductor doped with a small amount of pentavalent impurities, such As phosphorus (P) or arsenic (As). The combination of these two materials forms a pn junction.
2, the principle of diode:
On one side of the p-n junction, there are more holes in the p-type semiconductor than in the n-type semiconductor. When the diode is forward biased, that is, the anode is connected to the P region and the cathode is connected to the N region, holes and electrons will recombine to form a forward current. At this time, the diode is in a conducting state, and current can flow.
However, when the diode is reversely biased, that is, the anode is connected to the N region and the cathode is connected to the P region, because the minority carriers of electrons and holes cannot pass through the p-n junction, the current hardly flows. At this time, the diode is in the off state, and no current flows.
Practical application of diode;
1, rectifier:
Diodes can be used as rectifiers to convert AC electrical signals into DC signals. This is very common in power adapters, battery chargers, and power supplies for electronic equipment.
2. Regulator:
The zener diode can be used in the regulator circuit to stabilize the voltage output. This is usually used to stabilize the power supply circuit to ensure that the voltage in the circuit is constant.
3, light emitting diode:
LED is a special kind of diode, which can convert electric energy into light energy and is widely used in indicator light, display screen, lighting and other fields.
4. Switch:
Diodes can be used as switches. When the diode is forward biased, it is in a conducting state, allowing current to flow. However, when it is reverse biased, it is in the off state and the current will not flow. This makes diodes widely used in switching applications, such as logic gates and timer circuits.
5. Laser diode:
Laser diode is also a special kind of diode, which can produce high-intensity laser beam and be used in laser printers, laser indicators, medical equipment and other applications.