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Hi All,
I'm bored this afternoon, and thought maybe I'd get some thinking going on the general subject of reducing thermal losses in all electronic circuits. I deliberately leave out any superconductors or the like.
I've seen a number of approaches to this in the literature:
1) most commonly, using resonance to raise the voltage and reduce the current in a circuit-- resonance being an approximation to:
2) using adiabatic (ramp voltage) supplies and loads, as done in some experimental computers
3) using a T-network that creates a negative resistance, inductance or capacitance on one of the legs of the T, as used in filter circuits, developed by Tellegen and Bode
4) using a negative feedback amplifier and a hybrid circuit to feed back an inverted form of thermal noise, reducing it, as in Harold Black, and Robert Forward's gravitational detectors
5) using HF waves along a single wire, as in Tesla's experiments
6) using circuit elements made of thermoelectric materials, as in the Dotto Ring
Of course, this is a very heterogenous group of technologies, all that might reduce the thermal losses, or thermal noise, in a circuit composed of at least an R.
I think perhaps the most elegant, and simplest to apply, is the use of subharmonics. It turns out that resonance is not the most efficient state. This is implied by the fact that a ramp voltage is more efficient than a quarter sine voltage in the adiabatic computers. The paper by Boehler and Snider I recently uploaded has an interesting experiment. Just to make a point about whether charge memories had a future in nano tech, they show how the thermal losses due to the resistance in an RC (or presumably an RL) circuit are reduced, as the drive F is reduced relative to the resonant F.
We can start with any arbitrary R, and a time T we need energy to pass through this resistance. We then add a C (or L?) to this R, such that the time constant T1 of the resulting RC circuit is much shorter than the transfer time we need. Resistive losses in the circuit are reduced by T/T1. The practical limit is that systems already containing capacitance (or inductance?) have a built in 'time limit'. But when it comes to pure resistance you want to get rid of, just add your reactance, and drive at lower frequency than the RC.
Other methods seem to be a more sophisticated way of doing the same thing. Tellegen, the inventor of the gyrator, shows in an interesting patent that one can create a negative resistance along one leg of a T- or Star- connection, that cancels almost all of the R of that leg for one frequency. This was later used by Bode for improving frequency selection in filters. But the method seems to have much wider application than that. For instance, an arbitrary resonant circuit could have one of these passive filter type circuits imposed along its path, and the Q would be dramatically increased, substantially as if the circuit R would be dissolved.
Everything I'm saying is simply a reframing of well known and conventional physics, embodying the idea that "if you do things slower, you don't waste as much energy". But the principle does have wide application in electronics outside of adiabatic computers, where it has been stuck for decades.
A first use of such an invention would be the ramp charging of storage supercapacitors, and I've seen just a tiny interest in applying the idea in that area.
The other methods are generally stranger physics. I think the most interesting of these is the techniques first discussed by Harold Black and later used by Forward in the detection circuits for his huge gravitational detectors. Black used a negative feedback amplifier with a gain of 1, fed back through a hybrid transformer to cancel all the electron noise in the circuit. He reports that the circuit lost heat when it was working. I'm not sure why this technology isn't being used in High end audio equipment.
The rest I just put on there to see how many I could think of :-)
Regards,
Fred
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Author
Topic: Adiabatics, subresonance, and eliminating resistance (Read 2125 times)
