Assembling a simple Class-A Transistor Amplifier on a Breadboard

[@phillipneal8194]

Wonderful presentation. Clear, thoughtful, full of technique. Thank you

[@RobbyMatthias]

Excellent video! I would advise anyone trying to set-up 'bias' on a transistor to get your self a 'transistor-checking' meter!These are not 'horribly' expensive and they will give you the 'pin-out' of the transistor(EBC).The meter will also give you the (gain='hfe') of the transistor, which is important for (Audio-amplifier) circuits'.eg.fuzz-box,guitar,or guitar-amp,etc. The other piece of information the meter will give you,which is probably the most 'important',is that the transistor is 'NPN',or 'PNP',which are 'biased' differently!

[@LeonardCristescu-yk4vz]

Thank you for the lecture. It is very educational lesson.

[@ismoilova_shahina]

the most well-explained video on this topic. But it'd be awesome if you finished this amplifier )) cause I could've used it for my school project

[@davidleckie2431]

Hi Very interesting and well presented video. So many of the other videos try to cover too much. Couple of questions. Its an audio frequency amplifier. What design frequency of the blocking capacitors? 20Hz - 20KHz its a fairly big range. Its how you sized the 10µF capacitors? At a middle point of speech say 5KHz that gives an impedance of 3.2Ω Supposed you wanted to scale it up to an RF frequency say 15MHz(2MHz - 30MHz range) To have the same impedance of the blocking capacitor needs to be about 3000pF. Is that a reasonable assumption? What about the 33nF capacitor? How was it sized? Thanks for a great video. How about another one for RF frequencies? Regards Dave

[@EngineersAcademyLTD]

Hi David and thanks for your comment and kind feedback. This video is meant to be more as a breadboarding exercise, and to be honest, the component values used here were more driven by what I had on hand than any particular sizing requirements. Sizing the coupling capacitors 'correctly' involves knowledge of the input and output impedances to be connected. This thread gives some detail along the lines you discuss, for a similar circuit: electronics.stackexchange.com/questions/202848/how-to-size-coupling-and-bypass-capacitor-for-simple-bjt-ce-stage Hope this helps

[@Gcaga23]

Always thought the closest pin to the 'hat' of the transistor was the emitter. Maybe that's why my circuits with transistors haven't been working🤦‍♂

[@EngineersAcademyLTD]

It isn't consistent unfortunately and different transistors have different pin arrangements - always worth checking the datasheet for the transistor in question.

[@RobbyMatthias]

Best way is to use a 'transistor-checker' which will give you the pin-out,as well as 'hfe'=gain! I have the 'china-version' device, which is very useful for this information/data!

[@zalves2000]

Interesting, why are the capicitors with the positive towards the transistor?

[@EngineersAcademyLTD]

The capacitors are oriented with respect to the DC voltages within the circuit. So to the left of C1, the DC voltage is zero (not counting AC), whereas to the right of C1, the DC voltage is non-zero (determined by potential divider R1 and R2), so the capacitor is oriented in this direction.

[@zalves2000]

@@EngineersAcademyLTD thank you. Understood :)

[@Cubeone11]

hey can i use bc547 transistor

[@EngineersAcademyLTD]

Yes should be fine but check datasheet for pin arrangement