[GreenKeys] Loop Supplies (was: any missing USB-tty adapter orders?)

[Cory Heisterkamp]

If I recall it was in the neighborhood of 2k Ohm total. The power resistor
was an old Ohmite sliding-tap wirewound type to get me in the ballpark. The
rheostat probably started life as an old focus control for a B&W tv set.
Together there's enough adjustability to dial down to the high side of 20mA
for M32/33's and plenty of margin at 60mA for a chain of older machines. -C

On Wed, May 18, 2016 at 8:41 AM, Paul Birkel <pbirkel at gmail.com> wrote:

> Cory:  What values/wattage did you select for your power resistor and
> adjustable rheostat?
>
>
>
> *From:* GreenKeys [mailto:greenkeys-bounces at mailman.qth.net] *On Behalf
> Of *Cory Heisterkamp
> *Sent:* Tuesday, May 17, 2016 6:38 PM
> *To:* Greenkeys BOARD
> *Subject:* Re: [GreenKeys] any missing USB-tty adapter orders?
>
>
>
> Back in 2013 I decided I'd raid the parts stash for a power resistor and
> adjustable rheostat, then ordered a Hammond plastic project box and 1/4"
> insulated jacks off ebay <$10. Grabbed a mA meter there as well ($3.95) and
> ordered transformer 237-1270-ND from Digikey for $9.95. It may not have the
> efficiency of a modern design but it's served me well since then. Assembly
> time was less than an hour including drilling. I say go for it Ed!  -Cory
>
>
>
> On May 17, 2016, at 4:36 PM, Ed Sharpe Archivist for SMECC via GreenKeys
> wrote:
>
>
>
> what  we  need  now is the    one  board   60 mil  voltage  source  small
> and cheap! assembled...
>
>
>
> seriously will all the stuff I need to do ion a  days and nights  time I
> really  do not have    that much   time to build  things,....
>
>
>
> Eric's  boards  were an answer  to a long uttered  prayer!
>
>
>
> the  next thing that  would  be  cool is one with wireless network
> interface on it    and  sms?     well maybe  at  least the  wireless
> network.
>
>
>
> for  80 percent  of what  I am  doing these   usb boards  with the    push
> button to type message  fill the  bill.
>
>
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>
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