[Amps] Relay Reglulator / Driver

[Radio WC6W]

Hi Mike,
   First a couple of suppositions.

   1.  I presume that the "cut off voltage" is negative.
        &
   2.  It has enough extra current capability for the relays.

   You can use a LM337 with a preregulator.  Take a look at Linear Technology AN-2 to see how.

        or ...

   you could use a Texas Instruments TL783 positive regulator run "upside down" with it's input switched

        or... 

   you could eschew the regulator entirely and use a (simple two transistor) current source to feed the relay(s) -- If they're to be switched together they could be connected in series.

73 & Good evening,
   Marv WC6W 

http://wc6w.50webs.com/



--- On Tue, 7/21/09, MIKE DURKIN <patriot121 at msn.com> wrote:

> From: MIKE DURKIN <patriot121 at msn.com>
> Subject: [Amps] (no subject)
> To: amps at contesting.com
> Date: Tuesday, July 21, 2009, 2:30 PM
> 
> Hello ..
> 
> Im looking for a regulator in a (TO-220) to supply 28V for
> a few relays i picked up for my P9306UL (HL-2k) evil twin
> ... they are RF61-26S.
> I was hoping some one has a selector list - or the such, so
> that i could use the 85V cut off voltage as the supply
> voltage for the Tx/Rx relays.
> 
> KC7NOA
> 
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