[GreenKeys] 20mA circuit

[Ralph Mowery]

----- Original Message ----- 
From: <dmm at lemur.com>
To: <greenkeys at mailman.qth.net>
Sent: Wednesday, March 24, 2010 3:06 PM
Subject: [GreenKeys] 20mA circuit


>
> Lee Mushel wrote:
>>...
>>a Triad N-48X 115v:115v  15VA transformer (available back then) and then
>>...
>
> Actually, Mouser still lists it, and shows one in stock and 7 on order.
>
> Here's a question from the electronically challenged (me) - in the
> power supply you describe, what value would you suggest for the
> filter capacitor for a 60mA (not 20mA) supply?
>

Use what Hoff did in his ST series.  A 100 uF at 250 volts.  YOu can go up 
to double the uF value if you want to and a higher voltage also.  That is if 
you are using around a 100 to 150 volt transformer and about a 2000 to 2500 
ohm series resistor to limit the current.