Darlington Transistors and Using Them as Switches

Learn what Darlington transistors are and why they have such a large current gain (beta value). See why Darlington transistors are sometimes used as switches instead of regular BJTs.
Intro Song: Calabash by Co.fee
Extro Song: Enter the Tesla Machine by Tri-Tachyon
David Williams
www.elen.ca

[@AThreeDogNight]

A good explanation on the Darlington's, thank you for this video. As old as I am I'm starting to learn electronics all over from where I dropped off from them in the late 70's, so videos such as these are very helpful to the people who really want to learn these electronics of today, which has changed a lot since the 70's so once again thanks for a great explanation.

[@ElectronXLab]

Thanks for the comment, I appreciate it. I wish you all the best in your re-learning of these interesting topics.

[@rty1955]

As a EE I appreciate you approach to this using correct mathematical formulas. I see a lot of newbies to electronics that design by trial and error or fire and smoke as I call it. Electronics needs to be done methodical.

[@davidjohnston5329]

Fantastic explaination, especially the practical example at the end!

[@techankhamun838]

Very helpful and informative video! Thank you so much

[@robinbrowne5419]

I used to work at an electronics design house and we always used the TIP120 to control the speed of small motors with PWM. This was before MOSFETs became popular.

[@ohmedarick1]

Great Video . Great explanation Than you so much!!!

[@dylankirdahy9591]

Fantastic video, thank you!

[@caryrohan6157]

great video

[@Naga_9271]

Excellent explanation sir. Super 👌🏻👌🏻. Please upload more videos on electronics sir

[@mrHazzardous6]

If I had a voltage on the emitter side, like for example in a switching power converter circuit, how does one go about selecting an appropriate Rb? Because wouldn't the voltage be 3.3 - 1.4 - Ve, making it negative if Ve was large enough.

[@olivercouch1651]

Good video! Darlington Transistors can't' go into saturation though; the base emitter voltage would be higher than the collector emitter voltage of the large current transistor.

[@baotrungpham0427]

Where can I find the value of Curent Saturation for my transistor?

[@reptiloidx8942]

HELLO THERE . THERES A TIP142 NPN TRANSISTOR IM TRYING TO USE IN MY ONE TRANSISTOR SOUND AMP . SO TELL ME WHERE IS THE EXIT IS IT AN EMITTER OR COLLECTOR ???

[@shubhamnayak9369]

Sir you are using transistor in saturation and using relation Ic=beta.Ib But I have heard that above relation is true only when operated in active region then how are you using that relation in saturation??

[@edwinbenitez8621]

Where can I find the value of beta for my transistor?

[@ElectronXLab]

It will be on the datasheet for the transistor. The datasheet will usually give you a range, so if you want to know the beta of your transistor you would have to measure it. The problem is beta will also change based on temperature, so the best you can do is have a range of beta values.

[@googavo1d]

what if 1000 transistors arranged like Darlington ? what if infinitely many ?

[@iosyf8409]

why did you multiply Ic(sat) by 5 in the second part of the video? Isn't it just Ib= Ic(sat)/B

[@ElectronXLab]

Ib= Ic(sat)/B when the transistor is in the active region. For a switch, I want the transistor to be in saturation and in saturation, IB > IC(sat)/B, so to ensure that the transistor is well in to saturation, I want IB = 5 * IC(sat)/B

[@dhswede]

@@ElectronXLab The tutorial implies you picked a arbitrary factor of 5 to assure the transistor is in saturation ... should explain what the is the basis for 5X why not 2X or 10X.. surely 2 would be preferred over 10 since it would result in a smaller transistor to sufficiently handle a 5 A load. Should have reader to refer to the VA characteristic for transistor in question to determine an acceptable saturation current.

[@JontiFlashman]

oh churchie boys

[@ultimatebastiaan]

Well explained. Thanks. Also... FIRST!

[@lanasaespurofraude6899]

Hi good day, excellent videos and how to explain I wanted you to help me with a doubt HOW DO I MAKE A Darlington BUB941ZT WITH TWO CONVENTIONAL TRANSISTORS? WHAT do I have to take into account when combining them, can they be different or do they have to be the same? THE VOLTAGE THE CURRENT AND THE Hfe The darlntong that I need your data are Vceo 350 VOLTS Hfe 300 Ic 15 A POWER 150 watts

[@boonedockjourneyman7979]

Why would you choose to use a carefully designed linear component as a digital switch? There are dozens of components designed for the purpose. Good design is about proper selection not force fits.