Diodes

What is a Diode?

A diode is a semiconductor device, typically made of silicon, that acts as a one-way switch for current. It allows the current to flow through one direction while restricting its passage through the opposite direction.

Diodes are typically rated based on their voltage, type, and current-carrying capacity. Their polarity is based on an anode (positive lead) and cathode (negative lead). Most diodes allow current to flow only when the anode receives a positive voltage.

What is a Diode’s Purpose?

Diodes are primarily used for the following functions:

• Rectification: In a regular AC power supply, the direction of the current always changes. Diodes help regulate their flow by only allowing the current to move through the desired pathway.
• Radiowave Detection: Diodes help in the extraction of audio signals from radio waves.
• Voltage Control: Diodes help control voltages through a phenomenon called "breakdown voltage." This occurs when the voltage in the opposite direction exceeds a certain value, causing the current to start flowing in reverse.
• Current Conversion: Diodes are an important part of solar cells. When no voltage is applied from the outside, a solar cell acts as a battery, but when a voltage is applied, it acts as a diode.

What is a Symbol for Diode?

A diode symbol is a graphical representation used to denote its particular characteristics without the need for a physical inspection. It is typically depicted as a triangle pointing in the direction of a short line that is perpendicular to the current's path.

Types of Diode Symbol

Generic Diode Symbol

This symbol represents a generic diode or a rectifier diode. It is a semiconductor-based device that permits current to flow in one direction while obstructing its movement in the opposite direction.

Zener Diode Symbol

This symbol represents a Zener diode. This variant permits current flow in both directions, but only until the reverse voltage hits a specific value. After which, the current will flow in a single direction.

LED Diode Symbol

This symbol represents a light-emitting diode (LED). This is a type of P (layer)-N (layer) junction diode that emits light when placed in a forward direction. The strength of the light is determined by the energy gap of the semiconductor.

Photo Diode Symbol

This symbol represents a photodiode, a variant used to convert light energy into electricity. When light hits the P-N Junction, it creates an electron-hole pair that flows out as an electrical current.

Make Drawing Diode Symbols Easier With Capital X Panel Designer!

With so many different types of diode symbols out there, it can be a difficult task to draw them all out. Fortunately, you can skip the design process entirely with Capital X Panel Designer! This electrical CAD software comes with a library of pre-made diode symbols that you can simply drag and drop into your schematic layout, significantly boosting your production speed.

Learn more about how to create custom electrical symbols.