Long-Tailed Pair - Comparator and Differential Amplifier - Simply Put

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[@sandlertossone1813]

You know out of the hundreds of videos on this subject, I think you are the only one that actually goes through HOW to hook up the power supplies. I think most people doing circuits on KZbin just want to show what they can do as opposed to helping others. Thanks a ton

[@Sznycha]

Thank you Hagrid.

[@javierperez_21]

Thanks!!! Just discovered your channel and it is better than any other one in the internet

[@theguitaramptech]

I enjoy your intellect and your humility. Its a rare combination that makes for great viewing and learning. Thank you for going to so much effort. Its much appreciated.

[@Mqrius]

10:54 The reason you need the bottom resistor to be smaller than the top resistor, is that you're effectively making a voltage divider. If input 1 is very big, mosfet 2 is closed so we can ignore it, and mosfet 1 is fully open. Now you basically have a voltage divider with the top and bottom resistor. If your top resistor is 100 ohm and your bottom resistor is 10k, then the lowest output voltage you could possibly get is somewhere ~14/100 volts under your 9v top. Besides that, with such a high source voltage, the mosfet would stop conducting, so the whole thing stops working. With what you have now (10k up top, 4.7k on the bottom), your minimum output voltage is somewhere around 0 volts. If you make the top resistor bigger or the bottom resistor smaller, you could have a bigger swing. (Either way, the max output voltage is still the full 9v, achieved when the mosfet is closed.)

[@paulhbartley8030]

This has to be the very best explanation of differential pair operating principle that I have ever seen. The clincher for me was at 6:40 "When you change this transistor's biasing you end up changing this one's too?" (the answer being - no).

[@marceloalvarocoronelcastro3463]

Wow! I've been studying this subject for around a week reading books and experimenting but couldn't put in order all the conclusions I was getting and I was really confused and starting to get frustrated. You did a great job explaining everything man, thank you! Like + subscribe.

[@killianrocky3431]

instaBlaster

[@chrisclarke1587]

Very clear to me as i have forgot a lot of this since college and i am swatting up for my job interview. Thank you so much for your clear explanation.

[@nicksix71]

Bang on! I made the mistake of buying a certain book... by a certain you tube author. Pages of useless circuits. Thanks for a great video.

[@forgeteverythingyouknow5413]

It's pretty funny, Love How other people would describe Things Versus how you would describe them Yourself. . Thank you very much Was fun and I was entertained by the vastly Different ways people think. I find that very beneficial

[@stevencollins_uk]

Thanks for this! Really appreciate the simplified explanation and demonstrated circuit.

[@equalcrimeequaltime]

To get a high impedance you have to use PNP BJTs in a Darlington pair configuration. PNP isn't loading down your input signal being it sources current at the base also with Darlington pairs there's more impedance and it can pick up a signal of from ground up. The circuit performance gets even better if use a PNP current source and a pair of NPNs with their bases tied together and to the collector that you aren't getting the the output from(a current mirror) and if you put 2 NPNs on the output, you'll have a comparator that works just like the ICs do. Though to do it right, it takes 12 transistors for an open collector comparator with nearly perfect performance.

[@MarlonBrndo]

I haven't the slightest idea what I was listening too. But I was fascinated none the less

[@minle8702]

Brilliant ! Subscribed and liked . Very easy to listen to which makes the delivery easy to consume good pace n Low register voice kinda like Cronkite. Great production.

[@toastyt4013]

Hey man love the video. Your explanation helped me more than the others :) Also, you say "nmos" funny. I've always heard the "mos" part pronounced like "moss" that grows on a tree. So you say it like "N" + "moss".

[@K13SBike]

Ids explained very well , I always think of it as Igs

[@KetilDuna]

Nice story and very nice demo. I am a little curious about where the hammer comes in :) Thank you for sharing this.

[@vahagnmelikyan2906]

Ok so it's like 2 pipes with adjusted valves. If we open the valve on one of them little bit the water will flow little, and if we open the other pipe valve wider than more water will flow. And if we drill tiny holes on both of the pipes, the one pipe that has more water flowing will exit more water through the tiny output hole than the one that flows less? I didn't understand the voltage drop part. I always thought that mosfet is eighter on or off, didn't know you can have more current less current...

[@crazyahhkmed]

A transistor can be in one of three states. The first is off(no voltage/not enough voltage). The second is the linear region(amplification). The third is saturation. The "switching effect" occurs when the transistor is either off or in saturation. The linear (amplification) is skipped effectively. We do this by applying enough current or voltage( depends on transistor type) to put it in saturation. To understand transistors though, you really need to understand diodes and the basics chemistry/physics behind them. All diodes have a voltage drop caused by the voltage barrier at their internal pn junction.for silicon diodes this is about 0.7V, therefore you need a voltage atleast that high for the diode to "turn on". A transistor is basically two diodes with one being forward biased (ex: base - emitter) and the other reversed biased(ex: base-collector).

[@dell177]

Best explanation I've seen!

[@sherjeelshoaib89]

sir sir sir mister uuuuuu is there a word more then excellent or super excellent....u did really great thing

[@AdamTheAd-vanc3d]

Wow this is the best explanation I've heard, seen and watched. I thank you :-)

[@vahagnmelikyan2906]

But what causes the gates to receive different voltages. How is it accomplished?

[@Ureallydontknow]

True that you want low power for signal processing but if you go too far you get noise. There is definitely a sweet spot.

[@Tolye]

Thank you, mr Hagrid!

[@javierperez_21]

Why don't your headphones have speakers on them?

[@simplyput2796]

Because they turned out to be awful (despite being expensive), and rather than throw them away, I decided to use them as a mount for my little lapel microphone. I hollowed out the headphone pieces so I could hear normally, because if my hearing is muffled I talk weird.

[@parapos]

@@simplyput2796 i always wondered about this....

[@parapos]

great explanation, thank you. .....i still try to find a professor to ask for details....lol. ...so true. (it's frustrating actually)

[@bwack]

I wish I could explain it as good as you !

[@samlysinger234]

Excellent explanation and demo, thanks!

[@IIIDarkWorlDIII]

hahaha you spoke my heart man I loved your video! please keep uploading

[@JamrockVybzTV]

Great explaining

[@rommelbagasina7248]

But how did u get the difference between the outputs sir? I mean how should that be hooked up diagram-wise, I'm new to this

[@ahim20tfm]

Not all heroes wear capes

[@howtocreateresilience7009]

So 50x gain? Good video and that you show things from different perspectives. What's the upper limit for input voltages? And if it is really low, what are ways to increase it?

[@Firas95k]

Brother I wish you all the best 🌷

[@TheFlexXMLG]

I'm an absolute noob, but I just cannot understand why there's a bigger "voltage drop", when the transistor's current increases. Especially before the resistor. Can someone explain that?

[@t1d100]

Thank you for the video!

[@rommelbagasina7248]

YEEEEES FINALLLY!!!!!

[@vahagnmelikyan2906]

Good video but I'm having headache, how many times you have to cut the video footage.

[@kaoshavoc]

Thank you so much.

[@d.j.peters]

Well done.

[@rommelbagasina7248]

FINALLLLLLYYYY!!!!

[@josephsirois2353]

Thank you

[@JackHou-vw7hs]

Like and subscribed. Great explanation.

[@basterma]

Where is your circuit ground? You don't have any ground symbols in your diagrams.

[@aerofart]

Dude, you need to start making videos again . . .

[@MakerBrothers]

No. A long tailed pair isn't used to amplify the difference between two signals linearly, long tailed pairs are extremely non linear. you should have used two separate emitter resistors to ground. I show how a long tail pair really works in my video

[@realchristopher4334]

Oh yeah, it is 'him', I know. Alan Wolke. Radio code and KZbin channel is 'w2aew'.

[@nathanjaroszynski6210]

Well thanks. Thing one and thing two...

[@MrAlexstev]

you are the best,,,another Tesla

[@zotos7771]

You're crazy however most or all smart people are....