Re: capacitor transformer

On Sun, 05 Jun 2005 19:19:33 GMT, Jamie Morken <jmorken@xxxxxxx>
wrote:

>John Larkin wrote:
>> On Sat, 04 Jun 2005 20:04:52 GMT, Jamie Morken <jmorken@xxxxxxx>
>> wrote:
>>
>>
>>>Hi,
>>>
>>>Is there any application for using two electrostatically coupled
>>>capacitors to make a transformer? Would changing the ratio of plate
>>>area and plate seperation from the primary to secondary capacitor plates
>>>be able to control the voltage input and output ratios? This
>>>transformer would only be able to work with AC input just like an
>>>inductor based transformer, the main benefit I can see is that it works
>>>electrostatically so may not need an iron core to hold the EMF, and
>>>should be good for high frequency?
>>>
>>>cheers,
>>>Jamie
>>
>>
>>
>>
>> If by 'transformer' you mean a gadget that transfers power efficiently
>> between source and load of different impedance, there's no direct
>> capacitive equivalent of a transformer.
>
>In the simplest case I am really just thinking of a capacitor that has 4
>sheets seperated by dielectric, and the first and third sheet make one
>capacitor and the second and fourth sheet make the second capacitor, and
>this is all rolled up like a radial electrolytic cap, but with 4
>terminals instead of 2, corresponding to two seperate capacitors that
>are electrostatically coupled.
>

The "electrostatic coupling" is just more capacitance. So the whole
thing, circuit-wise, reduces to an array of capacitors, which doesn't
make a very useful transformer.

>If you can run AC into the "primary", ie. charging and discharging it at
>an average current of 1Amp over a 50volt range, then should you also not
>be able to extract a large portion of this power from the "secondary",
>if it is electrostatically coupled very well to the primary?

If the circuit reduces to a big cap connecting the source to the load,
sure you can get current to flow through it. But it's not a
transformer.

John


.

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