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Re: KV's and multimeters
From: Rick Holland[SMTP:rickh-at-ghg-dot-net]
Reply To: rickh-at-ghg-dot-net
Sent: Saturday, November 22, 1997 4:09 PM
To: Tesla List
Subject: Re: KV's and multimeters
Tesla List wrote:
<SNIP>
> Help!!!! The driver that I was talking about is now giving me seriuos
> problems. I replaced the TV transistor with a 3055 and the voltage was, as
> you said, increased, but the thing quit working. After trying a few things
> I decided to try a new 555, and it worked again, but quit again. I decided
> not to fry anymore 555 (thats what I was doing, and the things don't grow
> on trees!) so I wanted to ask you guys what I am doing wrong. Part of the
> problem may be that I need a higher voltage rated wire, but I don't know.
> The second time it only ran for a few seconds, and I didn't touch
> anything... Please tell me what I am doing wrong
>
> Thanks
> Matthew
You are probably feeding high frequency/high voltage spikes into the
supply voltage, caused by the reverse emf from the primary's magnetic
breakdown. Try isolating the supply to the 555 by using a resistor in
series from pin 8 to the supply voltage and a .1 to .01 uf capacitor
from pin 8 to ground. This dampens any high voltage through the resistor
and shorts any high frequency component to ground through the capacitor.
This may affect the operating frequency or duty cycle of the 555.
Alternatively you could use two power supplies, one for the oscillator
circuit and another to feed the 3055. Also, keep in mind that the 555
should not be operated above about 15V.
--
Rick Holland
The Answer is 42.