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Re: 50%
At 05:25 AM 11/6/96 +0000, you wrote:
>From ed-at-alumni.caltech.eduTue Nov 5 22:10:09 1996
>Date: Mon, 4 Nov 1996 20:16:46 -0800 (PST)
>From: "Edward V. Phillips" <ed-at-alumni.caltech.edu>
>To: tesla-at-pupman-dot-com
>Subject: Re: 50%
>
>Jack:
> Don't see how:
>"The voltage
>across the two capacitors after the reconnection is not V/2. It is V/sqrt2.
>This can be easily checked by test and correct algebra."
>can be correct. You now have TWICE the capacitance and
>1/SQR(2) the voltage. The CHARGE (C*V) is thus 2*C*V/SQR(2),
>or 1.414 etc times the original charge of CV! Can't be, as charge
>is most certainly conserved.
>Ed Phillips
>
---------------------------------------
Ed Phillips
Steve Roys
Ed Harris
Bert Hickman
Et al
I keep forgetting that I should be careful in replying to a problem that I
say is tricky. I should have done the testing first. I have now collected
data from tests that a friend and I made with the following results. The
tests were made at various voltages and with several different capacitors.
1. Voltage 2000 - Two 2500 pf/30KV caps - electrostatic meter - long time
constant - voltage dropped to V/2 when the connection to the second
capacitor was made.
2. Voltage 100 - Two 370 uf/200V/DC caps - Digital voltmeter - Voltage
dropped to V/2 but there was a big spark when the second capacitor was
connected. This indicates a large energy loss and voltage drop.
3.Voltage 7.96 and 3.96 - .2 farad/15V and .145 farad/15VDC caps - Digital
voltmeter - Some of the 7.96 volt tests had sparks when connecting to the
second cap - The 3.96 tests had no sparks - The voltage drop did not follow
the Coulomb Q = CV equation or the Energy J = 1/2 CV^2 equation. It was
estimated that the voltage drop for two equal capacitors would be between
V/2 and V/sqrt2.
Conclusion - All tests were made with large time constants so tests voltages
would be stable. The high voltage (2000) tests appeared to give voltage
drops of V/2. The medium voltage (100) tests also gave voltage drops to V/2
but when the sparking is considered the voltage would end up over V/2. The
low voltage (7.96 and 3.96) tests had little or no sparking and gave
estimated end voltages over V/2 for equal value capacitors.
None of the tests gave end voltages of V/sqrt2. However, this is probably
due to the sparking losses which would cause an additional voltage drop when
the second cap is connected. It appears that this test will give a V/2 end
voltage but because of the sparking voltage loss the true voltage is between
V/2 and V/sqrt2. The end voltage of V/2 may be misleading unless the
connecting to the second capacitor can be made without contact losses which
would mean only tests under about 4 volts can be used..
Jack C.