Diode Operation, Rectification, and Semiconductor Basics

Diode Bias: Direct and Reverse

A diode conducts electrical current only when its terminals are connected to the poles of a generator. It is then said that the diode has a bias and is in a state of conduction. If connected backwards, it is reverse biased and is in a state of deadlock, since no current passes.

Commercial Diodes

The symbol of the diode is an arrow indicating the direction in which the current can traverse. Germanium diodes have transparent encapsulation, and the line indicating the negative terminal is red.

Diode Rectification

The current that supplies the power grid, which we can access by connecting an apparatus to a plug, is common alternating current (AC). It is characterized by its polarity, which is continually changing 50 times per second. This type of current function is useful for powering bulbs, motors, etc.; however, electronic apparatuses such as TVs, videos, etc., operate on direct current (DC). Diodes are used to obtain current from the alternating current network, an operation known as alternating current rectification (e.g., a mobile phone charger).

Diode Bridge Chips

To build a diode bridge, four diodes and a good number of soldering joints are required. In the market, there are electronic components that facilitate the labor; these are integrated circuits (chips) that have a miniaturized diode bridge protected by a plastic capsule in their interior.

What is a Diode?

A diode is a semiconductor device that allows the passage of electric current in one direction with characteristics similar to a switch. In simple terms, the characteristic curve of a diode (I-V) consists of two regions: below a certain difference in potential, it behaves like an open circuit (non-conducting), and above it, it acts as a closed circuit with a very small electrical resistance.

Conductors

• Allow electric current to pass.
• Have very little resistance.
• Used to make wires and electrical connections.
• Examples: copper, iron, aluminum, etc.

Insulators

• Do not allow an electrical current to pass.
• Have a lot of resistance.
• Used to make coatings for cables, tool handles, etc.
• Examples: plastic, ceramic, and so on.

Semiconductors

• Allow a small amount of electric current to pass.
• Can be manipulated to behave as a conductor or insulator in certain situations.
• Examples: silicon, etc.