High Gain Transistor Circuits
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- เผยแพร่เมื่อ 4 มิ.ย. 2024
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/ theaudiophool
We're capping off our little series on transistor amplifiers by looking at how we can exctract a little more gain, bypassing the emitter resistor with a capacitor!
This builds on the last couple of videos so be sure to check those out of you haven't seen them!
Schematic: drive.google.com/file/d/1KFLq... - วิทยาศาสตร์และเทคโนโลยี
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Literally the best channel about electronics, you show different designs and explain why are they bad or good, and the way you explain things (theoretically then practically) is just amazing!
You are both a clever engr and a fine teacher.
Thanks for your work! You deserve more people watching your videos, because you are doing great explanations!
the algorithm needs to gift him more eyeballs
Thanks. I'm excited about the upcoming differential amp video, too!
I can't wait to see what more videos you'll produce it is so good :) I feel like experimenting with some transistors! (not right now though because i can't right now but you get me very excited!
Thanks dude! really appreciate these videos
Very good explanation. Just discovered you, and I like your teaching style
thank you for video
Proper interesting that was
As a former Sr. instructor, well done. Note for Americans , naught = 0😂
can you illustrate how to desigh a single ended high gain amp with active load and negative feedback?
i have popping problem when plugged in power jack on pnp transistor buffer
i built simple bjt buffer, what i missed?
thank you
ok so let's be ridiculous for a moment. for some crazy reason i decided to build single stage comon emiter amplifier of a gain around 100 times the input signal i have no idea what it is in decibels
it was for guitar preamp overdrive section and let's just say i wanted to blow every 100ma to roughly 10 Vpp with 12V power suply
it kind of works but the whole thing become really hissy i did limit the input signal to 700mV pp by clamping it with diodes in effect making it another distortion stage if signal ever get this hot (which it does) but next stage was tobe an overdrive anyway
would there be any better luck making that a multi stage thing or would internal hiss of a transistor increase with each stage. what causes the hiss anyway other than current flowing trough
i only amplified my signal 144 times including both buffer stagesand i kind of want it to only amplify the"music", will the capacitor bypas help anything with that?
It could be a lot of things causing the hiss! First thing I would try is halving all the resistors. That should help. You could try having a multi stage thing but as you guessed that just gives more opportunity for noise. The culprit is probably that your input signal is very quiet vs the noise. Noise can be a real pain!
I've been thinking about how to make a video about noise because there are lots of things you might not expect that can add noise
@@TheAudioPhool i can clamp imput to ground and the background hiss remains at the same level, i think it might be just one of the transistors by itself making that noise and i am not sure if with high gain is better to use low or high current trough a transistor. because i am not sure if i should care more for impedance (current amplification) or viltage gain and how that affect each stage
clamping a transistor with a cap on the colector is like clamping differential signal to ground so if it carry a copu of the hiss depending on it's phase it will either increase or decrease i think but with high gain it may be minimal difference
Yeah so you either need to cut the noise or raise the signal relative to the noise and reduce the gain. Noise can come from the transistor itself but could also come from high value resistors at the input. Have a play with some smaller resistors at the input if you can get away with it!
Wrt input impedance while low noise is important if you get a noise free signal that you have to amplify yet again because of input loading you might just end up with more noise!
Everyone does it on a bread bord I wanna see point to point hard wiring
the transistor amplifier easily yields a specified voltage. so, a resistor divider can produce a negative voltage supply rail, in a range we desire, from a stable DC source using this circuit.
so why are people introducing ripple into their euroracks with AC to AC convertors? i'd prefer to understand why this is, before blowing up my little parts :)
So is your question, why do people use AC-AC power supplies instead of just using a resistor divider with a transistor amplifier?
So for any transistor circuit you need the supply voltages first which must be higher/lower (depending on PNP/NPN) than the output voltage so you have to get the supply from somewhere!
If the question is more why do people use AC supplies at all, It's mostly because linear (i.e not switching) power supplies have lower noise, and that noise could leak into your circuits giving you noisy audio at the output.
I hope this answers your question! :) I intend to do videos on these very subjects so subscribe and keep an eye out!
@@TheAudioPhool cheers, it's been vexing to me, it's also been suggested that the ground produced by a resistor divider isn't isolated enough and produces incidental DC offset (ok for some stuff!). but truthfully, i think the important part of my question, is i'm too lazy to buy stuff to blow up. a solid understanding of electronics seems to require first hand effort to postulate circuits, and for decades i've always been the person incapable of admitting to myself that i haven't spent enough on proper gear (it's an aspect of teaching i wouldn't be surprised makes it into your channels questions from time to time).
ah, emitter degeneration feedback 😌