RC networks

Thread Starter

bobbyk

Joined Jun 13, 2006
12
The maximum gain value of 1.03 that I posted was way too low! I have
now found a 3-terminal RC network containing 2 resistors and 2 capacitors having a calculated open-circuit voltage gain of 1.15.
 

n9352527

Joined Oct 14, 2005
1,198
Could you post your circuit and calculations please? I'm curious whether there is any substance to your claim and whether I should update my old understanding of passive circuits due to what you've found.
 

hgmjr

Joined Jan 28, 2005
9,029
Bobbyk,

I would like to add my voice to the growing chorus of those urging you to post a diagram of your circuit along with details of your calculations. It would also be helpful for you to provide a description of the measurement method you used to confirm your calculations.

Without the requested information, there is no way for anyone to confirm your claims.

With all of the basic information at our fingertips, I am sure the AAC member community can arrive at a plausible explanation of your results.

In the end, if your claim of the existence of gain in a strictly passive component circuit containing no active gain elements is true, then it is safe to say that it flies in the face of generally accepted circuit theory.

hgmjr
 

Papabravo

Joined Feb 24, 2006
12,859
Bobbyk,

I'm not one to mince words and I believe that your claims are fraudulent. Ignorance of circuit theory would be forgivable. Obstinate vanity would not.
 

disantlor

Joined Jun 21, 2006
20
it's pretty clear he's just trying to goad us on at this point.

However in an attempt to salvage some value out of this thread I have a question (albeit one thats probably obvious to everyone but me).

Why does electromagnetic induction not represent a situation where the energy output is greater than the energy input. What I mean is that it seems to me like youre getting "free energy" in a sense. You're doing work to cause motion and getting additional energy.

Clearly I'm missing someone because I'm sure this is not some breakthrough in physics that no one thought of. Just wondering. Thanks
 

Ron H

Joined Apr 14, 2005
7,014
disantlor said:
it's pretty clear he's just trying to goad us on at this point.

However in an attempt to salvage some value out of this thread I have a question (albeit one thats probably obvious to everyone but me).

Why does electromagnetic induction not represent a situation where the energy output is greater than the energy input. What I mean is that it seems to me like youre getting "free energy" in a sense. You're doing work to cause motion and getting additional energy.

Clearly I'm missing someone because I'm sure this is not some breakthrough in physics that no one thought of. Just wondering. Thanks
But free energy would mean that you get more work out than you put in. That ain't gonna happen.
 

disantlor

Joined Jun 21, 2006
20
Ron H said:
But free energy would mean that you get more work out than you put in. That ain't gonna happen.
But thats what I'm saying, you're doing work to move an object, in this case a magnet through a coil of wire. In addition you're getting a current induced in the wire as a side effect of this motion. In a way it seems like you're getting something for nothing. I know it's kinda a stupid question, but you're using a certain amount of energy to get a certain amount of work (the moving object) but in addition youre getting energy in the wire, just because it happened to be in the right place at the right time, so to speak.
 

Ron H

Joined Apr 14, 2005
7,014
disantlor said:
But thats what I'm saying, you're doing work to move an object, in this case a magnet through a coil of wire. In addition you're getting a current induced in the wire as a side effect of this motion. In a way it seems like you're getting something for nothing. I know it's kinda a stupid question, but you're using a certain amount of energy to get a certain amount of work (the moving object) but in addition youre getting energy in the wire, just because it happened to be in the right place at the right time, so to speak.
If the wire weren't there, or it didn't have a current load on it, you wouldn't have to expend so much energy. If you want to get more power out, you have to put more in - with muscles, or diesel fuel, or falling water, or...
Here's a simple experiment. DC motors act as generators if you spin the rotor. Take a small one and spin the shaft. Now short out the terminals and spin it again. I think the point will be made.
 

Thread Starter

bobbyk

Joined Jun 13, 2006
12
Thanks for posting your over-unity-gain RC network, Ron H.
It really isn't all that profound, is it?

My 1.15-gain 4-element network has the same topology as your left-hand vertical string, except it only has your R4 (100K), R5 (1K), C4 (1n), and C5 (.1n). The bottom of C5 is grounded.

bobbyk

Correction --- C5 is .1 microfarad rather than .1n
 

disantlor

Joined Jun 21, 2006
20
Ron H said:
If the wire weren't there, or it didn't have a current load on it, you wouldn't have to expend so much energy. If you want to get more power out, you have to put more in - with muscles, or diesel fuel, or falling water, or...
Here's a simple experiment. DC motors act as generators if you spin the rotor. Take a small one and spin the shaft. Now short out the terminals and spin it again. I think the point will be made.
well I never actually knew that it was harder to spin the motor with the wire present. I guess I should have assumed that, but there's the explanation to my question. I told you it was a stupid one :)
 

Ron H

Joined Apr 14, 2005
7,014
bobbyk said:
Thanks for posting your over-unity-gain RC network, Ron H.
It really isn't all that profound, is it?

My 1.15-gain 4-element network has the same topology as your left-hand vertical string, except it only has your R4 (100K), R5 (1K), C4 (1n), and C5 (.1n). The bottom of C5 is grounded.

bobbyk
Not profound, maybe, but not obvious. I found the answer on Google Groups.
I'm curious why you were being coy. It didn't irritate me, because I had just stumbled onto the thread, But it irritated the crap out of some of the other guys.
 

Ron H

Joined Apr 14, 2005
7,014
disantlor said:
well I never actually knew that it was harder to spin the motor with the wire present. I guess I should have assumed that, but there's the explanation to my question. I told you it was a stupid one :)
It was not a stupid question.
 

Thread Starter

bobbyk

Joined Jun 13, 2006
12
Ron H said:
Not profound, maybe, but not obvious. I found the answer on Google Groups.
I'm curious why you were being coy. It didn't irritate me, because I had just stumbled onto the thread, But it irritated the crap out of some of the other guys.
Yeah, it seemed to!
 

Dave

Joined Nov 17, 2003
6,970
Whilst I am (currently) happy to let the tone of debate continue, can I remind members not to personally attack another forum member. It is fine to attack their arguements. Consider this a warning to all those participating in this debate.

Thank you.

Dave
 

Thread Starter

bobbyk

Joined Jun 13, 2006
12
bobbyk said:
Yeah, it seemed to!
Fine.

But, my original question was how large a gain can be acheived? It hasn't
been answered.

OK. this is a purely therotical question and has no basis in the real world.

Given an ideal linear 3-terminal RC network composed of an arbitrary number of resistors and capacitors of any value whatever connected in any manner whatsoever, what is the greatest magnitude of open-circuit
voltage gain for sinusoidal input?

I'm not being coy - I really don't know the answer
 

Ron H

Joined Apr 14, 2005
7,014
bobbyk said:
Fine.

But, my original question was how large a gain can be acheived? It hasn't
been answered.

OK. this is a purely therotical question and has no basis in the real world.

Given an ideal linear 3-terminal RC network composed of an arbitrary number of resistors and capacitors of any value whatever connected in any manner whatsoever, what is the greatest magnitude of open-circuit
voltage gain for sinusoidal input?

I'm not being coy - I really don't know the answer
I don't know the answer either. I did sim a circuit that has a maximum gain of 1.476. I also took your circuit, another R and C, and a couple of emitter followers and made a sine wave oscillator (simulated only).
 

Thread Starter

bobbyk

Joined Jun 13, 2006
12
How did you get 1.476? I've never been able to get a gain that large!
How many R's and C's did you need?

And thanks for your interest in this question! I think it's fascinating!
 
Top