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would a 15kv 5ua DC transformer work for TC
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From: Antonio Carlos M. de Queiroz [SMTP:acmq-at-compuland-dot-com.br]
Sent: Monday, February 23, 1998 12:20 AM
To: Tesla List
Subject: Re: would a 15kv 5ua DC transformer work for TC
Malcolm Watts wrote:
> The equation V = i x t/C would be helpful here. Let's say you want a
> break rate of 100 Hz. You have 10mS to charge the cap roughly.
> Assuming the supply *is* constant current up to 15kV, you can find a
> value of C that meets this requirement:
>
> C = 10^-5 x 10^-2/1.5x10^4 Farads = 6.6pF not too good really.
>
> Perhaps someone had better check my arithmetic.
It is correct, but...
Using the relation Voutmax=Vin*sqrt(C2/C1), and considering that C2
would be at least some 6.6 pF (only the self-capacitance of the
secondary coil), we obtain:
break rate capacitor maximum output voltage
100 6.6 pF 15 kV
10 66 pF 21 kV
1 666 pF 150 kV
A low-current supply can still produce some impressive output, if
you can make a low-leakage capacitor with 600 pF or more and use
a very low break rate. A large Leyden jar capacitor would be adequate.
With one break per second, the available energy for each discharge
would be 0.5*666e-12*(15000)^2=0.075 Joules, what can result
in a rather weak, but clearly visible, spark several inches (~3) long
considering the 150 kV.
(Some day I will try something like this using an electrostatic machine
to charge the primary capacitor, but with 60 kV instead of 15 kV.)
Antonio Carlos M. de Queiroz
http://www.coe.ufrj.br/~acmq