Re: LTSpice model for a SiC MOSFET

Bill Sloman <bill.sloman@ieee.org> wrote:

On 20/05/2025 7:58 pm, Liz Tuddenham wrote:

Bill Sloman <bill.sloman@ieee.org> wrote:
 
[...]

Capacitive divider using a spare core in the
mains supply lead as one plate of the capacitor?  (Depending on supply
frequency and required output current.)

>
I can't see how that could work.

 
If you used a three-core mains lead with one of the cores connected to
Neutral at the plug, one to Live at the plug and one floating, the
floating lead would take up a potential somewhere between the other two,
the stray capacitances between the leads acting as a capacitive divider.
 
The Live and Neutral leads are left unconnected at the equipment end and
the floating lead is connected to a rectifier system which takes it's
earth reference from the equipment being supplied.  It would be
approximately a constant-current supply, so a capacitor and zener diode
would be sufficient to stabilise it at the required low voltage.
 
The mains lead is acting as a high voltage capacitor but is a lot
cheaper and more reliable.
 
If you need a solid earth on the output, use a four-core cable.

 
That's a lot of words but doesn't describe anything that takes a small
direct current at high voltage and turns it into larger current at a low
voltage.

The original post didn't say that it was a direct current source.  My
comment "Depending on supply frequency and required output current."
would have given you a clue that I was assuming an A.C. source.

--
~ Liz Tuddenham ~
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www.poppyrecords.co.uk