Types of Diodes - The Learning Circuit

P-N junctions are considered your typical diodes. They have a p-n junction with a threshold voltage that has to be reached before current will flow through them. In silicon diodes, this is 0.7V. Once this is reached, the current will continue flowing. When hooked up backwards, in reverse bias, these diodes do not allow current to flow. If a diode is reverse bias, and it’s supplied with too much voltage, more than it’s breakdown voltage, it’ll “break-down” and current will flow through it in the wrong direction. Schottky diodes often look like typical diodes. But unlike p-n junction diodes, Schottky diodes have a metal-semiconductor junction. Silicon diodes require time for their depletion zone to grow and shrink when switching from allowing forward current to blocking reverse current. There’s a recovery time. Schottky junctions have no depletion zone. Because of their metal-semiconductor junction, Schottky diodes require virtually no recovery time and therefore have much faster switching speeds. This means they can handle switching current better and faster, which makes them useful in high frequency applications. They also have a lower forward voltage drop. Silicon diodes have a voltage drop of around 0.7V, but the voltage drop of Schottky diodes is between 0.15 V and 0.46 V. This means they lose less energy to heat, making them more efficient. Schottky diodes are not useful for all applications, as they can leak a small amount of current backwards. This could be problematic for certain circuits. While Schottky diodes can let some voltage leak through backwards, zener diodes are designed to allow current to flow in both directions. The p-n junction of zener diodes is heavily doped, only a specific voltage, the Zener voltage (Vz) can pass through without damaging the diode. In reverse bias, current will not flow through until the zener voltage is reached, but the voltage will be limited to the zener voltage. For example, a 3.3V zener diode will not allow current to flow until the supply voltage reaches 3.3V. If it’s supplied with 2V, no current flows. However, this diode could be supplied with 5, 6, 9, 12 Volts and it will regulate the voltage output to 3.3V. Zeners can have zener breakdown voltages of anywhere from 1.8V all the way up to 200V. LEDs, light emitting diodes, use energy from the particles moving through the p-n junction to create light. They can do this because they are made with gallium arsenide. Unlike silicon diodes, diodes made with gallium arsenide release energy in the form of light or photons. Like other diodes, they typically have 2 leads, though these can vary in length depending on the manufacturer. LEDs come in a wide variety of packages. Through-hole LEDs can be 3mm, 5mm, 10mm. They can have round and square lenses. Lenses can be clear or colored. 5mm round ones are the most common through-hole LEDs. Surface mount LEDs come in a variety of sizes as well. When choosing an LED, one of the first things you’ll look for is color, or wavelength. (Chart-VO) Here’s a chart of the color spectrum. Another choice you’ll have is beam angle or viewing angle. Beam angle is the amount of degrees where the light is visible. Depending on your application, you may want a narrow beam angle, like 10deg or a wide beam angle, like 120deg.

[mqblowe]

1:55 Most Replayed section + 0.25 playback speed. Very educational. 👍

[rrxlfks]

Karen,
we learnt these things in 1985. Its so refreshing the way you present things. In those days we had to go a grade up to grasp what was taught in lower grade. Electronics has been my favourite subject well before i started learning it. Its a passion.

[CrashFactory]

I am studying to get my amateur extra licence in amateur radio, and I can't tell you how handy these videos are!!!! THANKS!!!

[reasonablebeing]

Awesome overview of diodes. I would like to see some practical application examples in a future video.

[danielghani]

Moga Allah sentiasa merahmati puan, terima kasih sebab banyak membantu

[abhijitpatil]

You don't khow much much good work you are doing. I feel like I should have the professor like you while doing my Batchelor's. Keep the good work.

[neomags]

Gotta Love Karen.... taking something that could be rather boring and making it entertaining.

[pattyann]

i have been ordering LEDS from element14 and i am very happy with the company, , they are very nice people. great customer service. my name is Bobby Dunn and i live in Nebraska.

[WILL]

I love videos like this. Great descriptions of how all of this works. I've learned it all before, but its nice to see it described so succinctly and elegantly in one place. Keep making videos like this.

[letsgo]

Good work, I appreciate your effort for sharing your knowledge with us, I have two benifits from your videos,

1. I am improving my English
2. Getting knowledge 👍👍

[VISHALMOHAN]

Current will flow flow flow and flow. Awesome explaination.

[LordGarth]

the amount of information being put into these learning videos are getting better :D makes it harder to tell newbies to watch different basics video. I really like karen in these kinds of videos. 9/10 from me keep it up, the only down side is pronouncing zener as ze-ner rather than zen-er, but thats just a pet peeve and isnt a bad thing at all just prefrence

[oldestgamer]

I have found your videos to be a great resource for my students, thanks!

[larrybranscomb]

Excellent videos. I show them to my students in electronics classes.

[knuteriktornaas]

great video - very good explanations and illustrations

[seanbarron]

Loving the 'rapidly' face! 😂

[SciDOCMBC]

8:40 Albert Einstein received the Nobel Prize in 1921 for discovering the laws of the photoelectric effect. Unfortunately, it was not presented to him until December 10, 1922, since many members of the Nobel Prize Committee were skeptical about theoretical physics. This was also the reason why he did not receive a Nobel Prize for his theories of relativity, although the deflection of light by gravitation was already proven in 1919.

[iot_enthusiast]

and another video explaining the core concepts so well !

[adailyllama]

Learned something new about LEDs. Great video, as always, many thanks.

[technicalstudent]

Madam I see your all videos and it is very useful and enjoying videos