Transistor Bias Design

[thewayoutofdarkness]

This was a great video!!! I was curious about the final comment you made matching the impedance to the previous stage. I would love to see, if you get time, a video that expands on that concept with a simple example in the same genre of this video here. This is great stuff. Thank you for freely sharing. Very kind of you :)

[321reh]

I'm Trying to Go through all your videos to get Knowledge That's long gone and forgotten,,Thanks Rick...Keep up the GREAT WORK,,,321reh Loves It!!

[321reh]

Great Refresher For Anyone Including a Old Electronic Engineering Technologist Like Me!!!  Thanks Rick From You know Who!!??

[AllAmericanFiveRadio]

Thanks 321reh

[321reh]

Very Nice Explanation Here!!! Thanks Rick Regards Rick

[AllAmericanFiveRadio]

Thanks 321reh Rick

[radlam64]

I was thinking of using a high voltage NPN transistor like an MJE340 to drive a single ended valve like a 6V6. Would this bias method work OK for that application? B+ would be around 180-190VDC.

[AllAmericanFiveRadio]

@radlam64

My friends at K&K Audio use solid state to drive tube finals. I did a video about a year ago. I'll send you the vid and in the more information is the link to their website.

[AllAmericanFiveRadio]

@radlam64

I can't send you the video, this is the name of the video.

Audiophile, K&K Audio, Audio Amplifiers, Turn Table

[tutpal]

Nice information. Many thanks.

I always wanted to know the "way" to read a transistor datasheet.

Would apply your information and keep you posted with problems I face.

Regards,

--Utpal

[AllAmericanFiveRadio]

Thanks tutpal

[shaofu424]

well, whatya know, the little light, it came on! (bugs bunny ref) :) thanks...

[AllAmericanFiveRadio]

Thanks shaofu424

[joernone]

Rick,

Transistors are great, but there's no heater glow.  :-( Bell labs took the cool out of electronics. Or maybe I'm just stuck in the past lane, huh?

Thanks, my friend. Good vid.

Regards,

John

[AllAmericanFiveRadio]

@joernone

Thanks John,

Regards

Rick

[zigmaex]

Thank you for another carefully presented video.

[AllAmericanFiveRadio]

Thanks zigmaex

[aerofart]

Gain would certainly be a topic to cover, DC and AC gain. Also, how to choose a transistor. An online catalog showed there to be about 32,000 of them. If they are essentially all the same, either for switching or amplification, and their characteristics can be made uniform using the proper circuits, then why so many? You might also consider taking out one of those datasheets and explain to us what all those specs, charts, graphs and curves mean . . . at least for the benefit of us laypeople.

[aerofart]

1) Hi Rick, Great video, as usual. I've watched >almost< every one of your videos now and have enjoyed them all and learned quite a bit as well. Always leaving a thumbs up. I am fascinated by transistors, have always been since the age of about 7. I didn't understand them back then, and today, even after reading chapters on transistor biasing in several different books, I can hardly say I understand them much more today -barely. The calculus is mind-numbing, so I take the experimental

[aerofart]

2) approach, similar to what you've done in this video. I can usually and painlessly find the DC bias sweet-spot, but the real challenge in my estimation is how the AC(signal) component figures into all of this . . . in other words, how do the capacitors (and any inductors) fit into all of this???

[aerofart]

3) I really hope you can go into a series of videos and explain this for all of us. You know quite well how signals travel in the tube amps, so I'm sure you can explain to us non-mathematicians some practical ways to get our transistors to work with caps and inductors as well for impedance matching . . . don't see inductors much in modern circuits, least not in the stuff I'm tearing apart . . .

THANKS AGAIN FOR ALL YOUR GREAT WORK!!!

Sal

[AllAmericanFiveRadio]

Thanks aerofart

Hey Sal,

Looking at my most viewed videos, transistors are popular. That is why I did this one and was planing to do more. I think the next step would be to figure out the Beta, amplification factor, of a transistor and what it means. And then continue building and audio amplifier. I'll get one from a Zenith radio. Might as well use a real one from a radio that way we can do some troubleshooting too.

Rick

[aerofart]

@AllAmericanFiveRadio

That's a great idea, Rick. As much as I think IC's are the best thing since sliced bread (in general), I know that discrete components (especially Vac Tubes) have a special place in the realm of audio and analog applications. It would be nice to see you do an analysis, tear-down or build-up of a multi-stage audio amplifier, or maybe even something with RF, using tried-and-true discrete, analog circuits . . . something that an Old Ham might conjure up 50 years in . . .

[sjh7132]

R3 being 300 ohms is having a huge effect on your bias point. As the load R goes down, the current through R3 goes up, so the bias point goes up. So your chart is really only good for that value of R3.

Nice to see some old school electronics work! :-)

[AllAmericanFiveRadio]

Thanks sjh7132

A YouTuber thought that the highest bias of a transistor was about 0.67 volts. This demo blows that away. I'm hoping this makes it clear that the bias is mostly dependent on the LOAD, the purpose for the circuit. And the bias is influenced by the other parts of this circuit and is also influenced by the other circuits.

[muddymuddymuddmann]

Awesome and simple. thanks. Great tutorial.

MUDDy

[AllAmericanFiveRadio]

Thanks muddymuddymuddmann

[THEtechknight]

question, can you go into further detail on how to match cascading circuits? Thats the part I was hoping you would get to, but didnt.

[AndyDaviesByTheSea]

Nice informative video Rick and crisp graphics as usual, well done.

73's ... Andy

[AllAmericanFiveRadio]

@AndyDaviesByTheSea

Thanks Andy,

Regards Rick

[Mushketer888]

ive been waiting for that!

Thanks!

[AllAmericanFiveRadio]

Thanks Mushketer888

[famossfla]

Rick

Another great video....

I love your informative videos , but I have one question. When you describe a decimal value I notice you use DOT instead of POINT. Is there a professional significance in this ? or just the way we are brought up in Electronics ? If for example for 1.55volts if I say 1 point 55 volts. would I be wrong for using unprofessional slang.

Just wondering

Thanks

Amos

[bluuterra]

@famossfla

Rick, I hope he doesn't take that question as criticism. He's words are very measured and deliberate. He may have issues with criticism that would cause him to ruminate for hours and get nothing done. That would add time before the next video is produced. Why do you think he's teaching through his computer instead of in front of a class of wise-ass students? (I wonder if he'd like the video speed-up software that anajonser uses in his video's though) (youtube.com/user/anajonesr)

[AllAmericanFiveRadio]

@bluuterra

Oh, I taught engineers software for over ten years and all over the world too. Here on YouTube I usually do a, BlockUse and Delete, twice a week, sometimes more.

[AllAmericanFiveRadio]

@famossfla

Hey Amos,

lol, I got in the habit of saying DOT because I taught software for over ten years. And now the Internet, which is software.

Regards

Rick

[quantumbits]

@AllAmericanFiveRadio Also very common practice in radio communications. IE: for 14.250MHz; One, four, dot, two, five, zero, Megahertz.

[eeadata]

first view!! Nice vid

[AllAmericanFiveRadio]

Thanks eeadata