In Reply to: Re: What happens to back EMF with a feedback amplifier? posted by Soundmind on August 17, 2006 at 08:04:51:
"Transistors are especially effective at this having very low inherent output impedence"Yes its low but only in the forward direction. The back EMF will meet high resistance trying to go through the transistor the wrong way and then the feedback loop looks like an appetizing lower resistance path, does it not? My understanding of electronics is not so poor that I don't know the path of least resistance is the one taken. The greater the feedback the lower the resistance of the feedback loop if I am not mistaken.
"One characteristic of negative feedback is that it tends to reduce output impedence thereby more effectively dissipating reverse EMF"
Yes it reduces output impedance but how exactly? THe impedance of the device itself is a fixed value (for a given temperature and operating voltage) but high feedback makes a low impedance loop back to the input. 100% feedback is simply a wire attached from out to in and I can bet that the EMF wouldn't be disipated at the output transistors then! It seems to me that High negative feedback would simply shunt the back EMF right to the input where it will be amplified. With a tube and no feedback you have a true barrier from EMF getting back into the system. It is simply dissipated at the Plate as heat. My engineer friend told me that the same is not guaranteed with transistors because that semiconductor layer is mighty thin.
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Follow Ups
- Re: What happens to back EMF with a feedback amplifier? - morricab 09:45:44 08/17/06 (49)
- Now I see it was just a troll. - clifff 13:31:28 08/17/06 (12)
- Re: Now I see it was just a troll. - morricab 14:43:14 08/17/06 (10)
- All of it. You are not listening. nt - clifff 01:06:56 08/18/06 (8)
- Re: All of it. You are not listening. nt - morricab 02:10:46 08/18/06 (7)
- Morricab....you are not listening. - Soundmind 15:22:07 08/18/06 (0)
- Your claims/responses here and elsewhere. - clifff 03:59:57 08/18/06 (5)
- Re: Your claims/responses here and elsewhere. - morricab 05:16:34 08/18/06 (4)
- You give the sneering man far more than he deserves, but bless you anyway. nt - clarkjohnsen 07:29:49 08/18/06 (3)
- Re: You give the sneering man far more than he deserves, but bless you anyway. nt - morricab 11:43:58 08/18/06 (2)
- I know how you do a snarl (grrrrrrrrr...) but how do you do a sneer? nt - clarkjohnsen 12:35:07 08/18/06 (1)
- Based on your postings clark it seems to me your face must be permanently deformed into a sneer - Soundmind 08:13:06 08/19/06 (0)
- If it talks like a troll, walks like a troll, and looks like a troll............ - Dan Banquer 17:13:22 08/17/06 (0)
- Your Owns Words Coming Back To Haunt You Cliff? - thetubeguy1954 14:00:25 08/17/06 (0)
- You are dead wrong....as usual - Soundmind 10:22:48 08/17/06 (35)
- Re: You are dead wrong....as usual - morricab 13:10:35 08/17/06 (30)
- Re: You are dead wrong....again& again & again - Dan Banquer 18:25:05 08/17/06 (21)
- Re: You are dead wrong....again& again & again - morricab 05:32:51 08/18/06 (20)
- Re: You are dead wrong....again& again & again - Dan Banquer 07:22:03 08/18/06 (19)
- Re: You are dead wrong....again& again & again - morricab 08:28:02 08/18/06 (18)
- Once again Troll - Dan Banquer 08:57:48 08/18/06 (17)
- Re: Once again Troll - morricab 11:26:14 08/18/06 (1)
- Re: Once again Troll - Dan Banquer 12:58:57 08/18/06 (0)
- Re: Once again Troll - john curl 09:25:55 08/18/06 (0)
- Re: Once again Troll - john curl 09:21:06 08/18/06 (10)
- Re: Once again Troll - Soundmind 09:50:50 08/18/06 (0)
- DUH! - Dan Banquer 09:36:20 08/18/06 (8)
- Re: DUH! - john curl 09:50:37 08/18/06 (7)
- Re: DUH! - Dan Banquer 10:28:49 08/18/06 (6)
- Re: DUH! - morricab 11:45:14 08/18/06 (5)
- Well, it does put perspective into his frame of reference - E-Stat 15:11:00 08/18/06 (2)
- Re: Well, it does put perspective into his frame of reference - AJinFLA 17:15:47 08/18/06 (1)
- Not at all - E-Stat 17:26:17 08/18/06 (0)
- Re: DUH! - Dan Banquer 12:57:04 08/18/06 (1)
- Re: DUH! - morricab 16:56:02 08/18/06 (0)
- And Furthermore troll - Dan Banquer 09:18:15 08/18/06 (2)
- Re: And Furthermore troll - morricab 11:14:10 08/18/06 (1)
- Someone has to be the head of the meritocracy... - Wellfed 11:21:17 08/18/06 (0)
- If you want to understand what negative feedback is really about....read a text, solve the equations - Soundmind 13:37:27 08/17/06 (7)
- See my post to Dan above, you are wrong . - morricab 05:34:08 08/18/06 (1)
- Still trolling I see - Dan Banquer 07:34:55 08/18/06 (1)
- Re: If you want to understand what negative feedback is really about....read a text, solve the equations - john curl 15:01:24 08/17/06 (3)
- Re: If you want to understand what negative feedback is really about....read a text, solve the equations - clifff 01:08:31 08/18/06 (2)
- Re: If you want to understand what negative feedback is really about....read a text, solve the equations - Soundmind 04:44:33 08/18/06 (1)
- Answer - E-Stat 15:34:22 08/18/06 (0)
- Re: If you want to understand what negative feedback is really about....read a text, solve the equations - morricab 14:07:00 08/17/06 (0)
- Damping factor - Dan Banquer 11:50:47 08/17/06 (3)
- Re: Damping factor - morricab 12:56:31 08/17/06 (2)
- Idiot Child Strikes Again - Dan Banquer 13:12:05 08/17/06 (1)
- Pot calling the kettle black - morricab 14:39:05 08/17/06 (0)