A diode is a specialized electronic component that has two electrodes: the cathode and the anode. Many of them are made out of semiconductor materials such as selenium, germanium, or silicon. They can be used as signal mixers, oscillators, signal limiters, voltage regulators, signal modulators, and switches.
What are the different types of diodes?
- Backward diode: It is a type of PN junction diode and operates similarly to the tunnel diode.
- BARIT diode: This diode operates on the property of barrier injection transit time which is where it gets its name from. It is popular in microwaves.
- Light Emitting Diode: When current flows through this diode's junction, light is emitted. It uses component semiconductors that can produce an array of colors.
- Photodiode: A photodiode is used in light detection. It operates under reverse bias circumstances whereby even a small amount of current coming from the light would be easily detected. They are used in electricity generation.
- PIN diode: It contains the standard N-type and P-type sections, and between them, there is a section of intrinsic semiconductor that has no doping. These are particularly useful for switching applications.
- Laser diode: This one produces coherent light and is common among CD and DVD drives as well as in laser light pointers used for presentations.
What are some of the applications of diodes?
- Power Conversion: Diodes can convert AC power into DC power. They do this by forming a full-wave (four diodes) or a half-way (single diodes) rectifier. As a result, only a section of the AC waveform is allowed to travel through it. Upon charging a capacitor, the voltage of the output will resemble that of a steady DC voltage.
- Demodulation of Signals: Diodes are able to get rid of the negative components of an AC signal thus making it easier to work with other electrical devices. Very little information is lost in this process and, as such, they are used in the filtering process in radios to aid in the extraction of radio signals from the carrier wave.
- Current Steering: Diodes basically steer current only in one direction. Its current steering capability is particularly used in the switching of power from a power supply so that it is able to run from a battery. For example, when a device is plugged and charging a cell phone, the diode helps draw current exclusively from the external power supply, not the battery.
- Over-Voltage Protection: Diodes also serve as protection devices when it comes to sensitive electronic components. Here, they promptly short high voltage spikes to the ground, thus preventing damage to an integrated circuit.
What are some of the characteristics of a diode?
One of the characteristics of a diode is the forward voltage drop. In forward bias circumstances, this should be approximately seven volts. The other characteristic is the reverse voltage drop. When you reverse bias a diode, the layer of depletion widens and the applied voltage is felt across the diode. The last characteristic is the reverse breakdown voltage. When there is a reverse voltage drop, the current flow is reversed thus destroying the diode.