(unknown)

Russell wrote:
> On Fri, 16 May 2025 at 03:48, John Lawton <[email protected]> wrote:
> > I experienced interference on a nearby AM radio, IIRC the cure was to
> > add a capacitor across the transformer secondary.
> >
> > A series resistor from diodes to cap spreads the conduction angle.
> 
> Effect of cap across transformer "would need thinking about".
> 
> In ye good olde days with high voltage tube supplies (807s at 1200V?) it
> was not uncommon to see diode strings (to achieve high enough voltage) with
> resistors in parallel with each diode. I'm getting old :-)

Yes. Resistors to mitigate the variations in leakage current values among
the diodes, and also a capacitor in parallel with each diode to mitigate the
variations in switching speed among them.

In both cases, it prevents the "better" diodes (lower leakage, faster
switching) from experiencing excessively high reverse voltages.

-- Dave