diode

A diode is a device for controlling electrical currents so that they only flow the desired way (the way the engineer wants them to).

Diodes are used in all kinds of electronic devices. Most diodes in use today are semiconductor diodes. People often simply use the word diode when they are talking about a semiconductor diode. A semiconductor is a material that electricity can travel through, but not as well as when it travels through a stronger conductor like copper. This kind of diode is kind of like a door for electricity to move through, but it only opens one way.

Among the simplest kinds of this device are p-n junction diodes. Such diodes are commonly made from the semiconductor silicon. Silicon doesn’t conduct very well on its own, but its conductivity can be improved by adding other elements. Depending on what you add to the silicon, it can become either what’s called a p-type material, which has a positive charge, or an n-type material, which has a negative charge.  To create the diode, some p-type material and n-type material are put together. The p-type is the anode, and the n-type is the cathode. At the junction, where the two materials meet, they cancel each other out, and the area around the junction doesn’t have a charge. The electrical current can’t cross it. If you add a positive electrical current to the positive end and a negative one to the negative end, the junction gets smaller and electricity can flow across the junction. But if you reverse that, the junction gets bigger and the current can’t go across. So electricity can only be conducted in one direction, and the diode is created.

Another basic type of diode is the thermionic diode. You might know these better as vacuum tubes. Vacuum tubes use glass tubes to create a vacuum surrounding a tiny wire, which heats up the cathode and releases electrons. The anode then attracts the electrons, which means the current goes in that direction. Though this type of diode was common in early electrical applications, it’s largely been replaced by the semiconductor type today.

The term LED (as in LED lights and LED bulbs) stands for light-emitting diode. Some semiconductor diodes are so flexible and powerful that they can be made to produce light. This makes LED bulbs more efficient than standard light bulbs.

Example: The device malfunctioned due to a faulty diode, but it was easy to replace.

The first record of the word diode as a noun in an electrical context is believed to come from a 1919 article by engineer William Henry Eccles, who used the word as term for a “tube with two electrodes.” It is a combination of di-, meaning “two,” and -ode, which means “way” or “road” and is used in many electrical and electronics terms, including anode, cathode, and electrode.

Based on its etymology, it sounds like a diode is a two-way street for electrical currents. However, in practice, the typical function of a diode is to control electrical current so that it flows in one direction.

What are some synonyms for diode?

• semiconductor diode

What are some words that share a root or word element with diode? 

• light-emitting diode
• LED
• diode laser
• anode
• cathode
• electrode

What are some words that often get used in discussing diode?

• semiconductor
• p-n junction
• electrical
• electronics
• component
• part
• current
• device
• silicon

Diodes are very commonly used in many different kinds of electronics, but the word itself is typically only used in technical contexts.

Nov 20, 1906, Greenleaf Whittier Pickard receives his crystal (cat's whisker) detector patent to receive #radio broadcasts. 1st type of semiconductor diode, laying the groundwork for Bell Labs' transistor invention 42 years later. #OTD #STEM #ThisDayinSTEM https://t.co/y1sRnk5jjP pic.twitter.com/CrZV7Raodg

— Bell Labs (@BellLabs) November 20, 2017

Dynamic Redistribution of Mobile Ions in Perovskite Light-Emitting Diodes (relevance: 86%) https://t.co/3dpg63i18n #battchat #batterytwitter pic.twitter.com/C0eYJLer9J

— electrochemicat (@electrochemicat) November 23, 2020

Did you know? A photovoltaic cell (PV cell) is a specialized semiconductor diode that converts visible light into direct current (DC). #solarsquad #solar #squad #solarpower #solarenergy #solarpanels #solarthermal #renewableenergy #solarfacts #didyouknow #projectreservoir #funfact pic.twitter.com/lQXVguzctf

— Solar Squad (@SquadSolar) February 11, 2019

True or False? 

Many diodes are semiconductor diodes.