I did this stuff exactly 50 years ago in a lecture theatre at Manakau Tech. The teacher basically read from the text and drew the necessary things, but wasn't feeling it like we saw here. There was no connection, just repetition. I wonder if he actually understood the material? By contrast, this time he seemed to feel those voltages, electron flows and AC signals. If this, then that, because... - that is just brilliant and imparts true knowledge to the class. How i wish this man had been our teacher. I got more from this vid than prolly 10 hours of formal amp design in 1974. Am going to run this up on a breadboard with a 2n2222 or BC54-something and see the output signal change, based on calculations and experiment. And I'm sure it'll work better than those labs at MTI. Thank you, I've subscribed and want lots more!
Would not a diode rectify that part of the AC signal above 0.7v ( if the input was say 2v peak to peak) So there would be an amplified output of the input?
Why is the AC coupling capacitor added at the emitter to increase gain if the primary purpose of most of the other additional components are to decrease gain and decrease the significance of the transistor's natural hFE? If this bypasses the emitter resistor why is it needed in the first place?
Keep in mind that the signal current is a.c., but the working (supply) current of the amplifier circuit is d.c. So, the bypass capacitor does bypass the signal current, but ONLY the signal current: the d.c. supply current still "sees" the emitter resistance, so it continues to maintain the proper circuit bias.
Interesting.
I did this stuff exactly 50 years ago in a lecture theatre at Manakau Tech. The teacher basically read from the text and drew the necessary things, but wasn't feeling it like we saw here. There was no connection, just repetition. I wonder if he actually understood the material?
By contrast, this time he seemed to feel those voltages, electron flows and AC signals. If this, then that, because... - that is just brilliant and imparts true knowledge to the class. How i wish this man had been our teacher. I got more from this vid than prolly 10 hours of formal amp design in 1974.
Am going to run this up on a breadboard with a 2n2222 or BC54-something and see the output signal change, based on calculations and experiment. And I'm sure it'll work better than those labs at MTI.
Thank you, I've subscribed and want lots more!
The diode also has a 0.7 voltage drop so everything beneath 0.7 volts wil not be amplified
Yup, he said this and even drew a little graph, remember? He started at 0.5V...
Shouldnt the capacitor be polarized? Or the non polarized ones would work just fine?
Would not a diode rectify that part of the AC signal above 0.7v ( if the input was say 2v peak to peak) So there would be an amplified output of the input?
Why is the AC coupling capacitor added at the emitter to increase gain if the primary purpose of most of the other additional components are to decrease gain and decrease the significance of the transistor's natural hFE? If this bypasses the emitter resistor why is it needed in the first place?
Keep in mind that the signal current is a.c., but the working (supply) current of the amplifier circuit is d.c. So, the bypass capacitor does bypass the signal current, but ONLY the signal current: the d.c. supply current still "sees" the emitter resistance, so it continues to maintain the proper circuit bias.
Oh, Ok Bob. I thought MY autofocus, wasn't working!
No more "Dave" guest appearances please!