Diode PN Junction (ELECTRONICS)

Diode PN Junction :

Well, a diode is an electronic component that conducts current in one direction and blocks current flow in the other direction.

How to connect a diode

Let’s look at an example.

In the above circuit, the diode is connected in the correct direction. This means that current can flow through it to make the LED turn on.

But what happens if we connect it backwards?

In this second circuit the diode is connected incorrectly. This means that no current will flow in the circuit and the LED will turn off.

What is a diode used for?

Diodes are very frequently used in power supplies. Alternating current (AC) is obtained from the wall outlet. Many of the devices we use require direct current (DC). To get DC from AC we need a rectifier circuit. It is a circuit that converts alternating current (AC) to direct current (DC). Diodes are the main components of rectifier circuits.

How a diode works:

The diode is created from a PN junction. A PN junction is obtained by taking negative and positive doped semiconductor material and joining them together.

At the intersection of these two materials a “depletion region” appears. This depletion region acts as an insulator and refuses to allow current to pass.

When a positive voltage is applied from the positive side to the negative side, the “depletion layer” between the two materials disappears and current can flow from the positive side to the negative side.

When a voltage is applied in the other direction, from the negative to the positive side, the depletion region expands and resists any current flow.

Things to keep in mind about diodes

• You must apply enough voltage in the “correct” direction (positive to negative) for the diode to start conducting. Normally this voltage is around 0.7V.

• The diode has limits and cannot conduct unlimited amounts of current.

• Diodes are not perfect components. If you apply voltage in the wrong direction, a little current will flow. This current is called “leakage current”.

• If you apply a high enough voltage in the “wrong” direction, the diode will break down and let current flow in that direction as well.

Types of Diodes:

There are many different types of diodes. The most common are signal diodes, rectifier diodes, zener diodes and light emitting diodes (LEDs). Signal and rectifier diodes are practically the same, except that rectifier diodes are designed to

Types of diodes

There are many different types of diodes. The most common are signal diodes, rectifier diodes, zener diodes and light emitting diodes (LEDs). Signal and rectifier diodes are practically the same thing, except that rectifier diodes are designed to handle more power.

Zener diodes are diodes that use breakdown voltage when voltage is applied “incorrectly.” They act as very stable voltage references.