[AMRadio] More Boring Voltage Regulators

[Jim Candela]

Joe,
 
   You make a good point. I guess I am a glutten for punishment. Anyway a rule of thumb for air dialectric with rounded electrodes is 10KV / inch. Having two nail points looking at eah other will be less. So in my case, that translates to 1kv per 1/10 inch. Put some wires on the ic pins, and the gap is reduced to about .05", or 500 volts. I was planning to use some sort of conformal coat over the back side of the board, and around the ic header sockets. I am not sure what to use, but was pondering Krylon clear coat spray. Anybody have experience with conformal coating pcb's, and if so what compound did they use?
  For now, the board is clean and dry, and no arcing has ocurred. I used 24 awg buss wire with teflon tubing as a sleeve. I was looking last night at my ic header pinout, and I could have done a better job to minimize pin to pin voltage stress. Oh well...next time!
 
Thanks for the comments!
Jim

Joseph Bento <n6dgy at kirtland.com> wrote:
I don't recall what the equation was for a spark gap and voltage 
breakdown. I'd feel a bit leary of using a 16pin header with 500 volts 
applied though. Considering theat the pin spacing is .1" there's not a 
lot of protection for flashover.

Using solid state regulators for high voltage is fine, but I'd be more 
inclined to build the circuit on a terminal board, or etch a PC board 
for the regulator, using wide spaced traces.

Joe



Jim candela wrote:

>PS Some of this circuitry can be applied to AM radios...just to stay on
>topic. Go ahead and call me crazy for running a dc fan at high common mode
>voltage, and putting 450 volts to a header plugged into a ic socket. It
>would just confirm what I already know.
> 
>


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