Rat Shack did it to themselves. They blew it big time. And in multiple ways. With a nationwide distribution network they were perfectly poised to be major players in the PC revolution. But what did we get? The Trash 80! There was even a time when RS offered oscilloscopes for sale but what did they do? They hitched their wagon to multimeters. Which are good instruments but we could have had so much more.
It hurts a transistor's capability as a current amplifier if it cannot modulate the current passing from collector to emitter. It would either saturate at the current of the constant current source or be cut off at the maximum voltage the constant current source can supply.
Am I right in assuming that the resistance to current flow from base to ground through the emitter is so high that no current will pass an hence there is not enough voltage dropped across the junction to cause conduction?
This circuit allready has a very high input resistance. And this is also the reason of the very high input resistance of BJT op amps to common mode signals. It is sometimes orders of magnitude higher than the differential mode input resistance.
As I understand, there is a very strong resistive feedback degrading the gain. It would be sweet to see the base-to-emitter voltage at the same time with the emitter voltage. Maybe they are in opposite phase?
@@JohnAudioTech I've used this trick before in tube circuits ... you end up with a voltage gain equal to the µ of the tube! Pretty handy if you need it!
maybe someone can help me? I have a preamplifier in a small box with external power supply. The preamplifier card should have 15v-0v-15v To make it easier, I use a regular AC adapter and 2 diodes and 2 capacitors (volt doubles) but I get 50 Hz noise. when I plug out the power adapter and before the capacitors are discharged the noise disappears but there is still music for 2-3 seconds. why? does anyone have the answer to that? With current from capacitors, 50hz is completely gone I have tried large capacitors and several AC adapters without this having helped.
![เปิด อาณาจักร หมื่นล้าน "สาระตั้ม" l [Nickynachat]](http://i.ytimg.com/vi/3XE0nPF4YkQ/mqdefault.jpg)
Does anybody else miss RadioShack as much as I do?..
Thank you John!!!
Rat Shack did it to themselves. They blew it big time. And in multiple ways. With a nationwide distribution network they were perfectly poised to be major players in the PC revolution. But what did we get? The Trash 80! There was even a time when RS offered oscilloscopes for sale but what did they do? They hitched their wagon to multimeters. Which are good instruments but we could have had so much more.
Nicely explained John your a great teacher.
excellently explained! A special view of a simple circuit... Thanks John
Great explanation - i love your videos John, please keep them coming.
Good one John. Nicely explained. Quite unpractical as a circuit, but a nice experiment, a bit like hammering a hot piece of steel, without an anvil.
Great stuff, John, Interesting as always.
Good stuff, John !
Very nice, great information, thanks
Good informative video
thx John
It hurts a transistor's capability as a current amplifier if it cannot modulate the current passing from collector to emitter. It would either saturate at the current of the constant current source or be cut off at the maximum voltage the constant current source can supply.
Creative video, like it, thanks for sharing :)
Am I right in assuming that the resistance to current flow from base to ground through the emitter is so high that no current will pass an hence there is not enough voltage dropped across the junction to cause conduction?
You can also take the signal from the emitter, to have a very high input impedence.
This circuit allready has a very high input resistance. And this is also the reason of the very high input resistance of BJT op amps to common mode signals. It is sometimes orders of magnitude higher than the differential mode input resistance.
You got an emitter follower….
Good Information 😍😍
As I understand, there is a very strong resistive feedback degrading the gain. It would be sweet to see the base-to-emitter voltage at the same time with the emitter voltage. Maybe they are in opposite phase?
Emitter signal is in phase with the base or this would not work. At higher frequencies there can be a phase shift due to junction capacitance though.
Next do the CCS at the collector!
infinite gain!
@@JohnAudioTech I've used this trick before in tube circuits ... you end up with a voltage gain equal to the µ of the tube! Pretty handy if you need it!
maybe someone can help me?
I have a preamplifier in a small box with external power supply. The preamplifier card should have 15v-0v-15v
To make it easier, I use a regular AC adapter and 2 diodes and 2 capacitors (volt doubles) but I get 50 Hz noise. when I plug out the power adapter and before the capacitors are discharged the noise disappears but there is still music for 2-3 seconds. why? does anyone have the answer to that? With current from capacitors, 50hz is completely gone
I have tried large capacitors and several AC adapters without this having helped.
Is the output of your "AC adapter and 2 diodes and 2 capacitors" a DC output or AC?
Your video length is 737