[Boatanchors] 51J4 Muting 12v PS?

[WA5CAB at cs.com]

Eugene,

Because you really don't know how bad the regulation is until you check it, 
and because 200 mA is probably a lot more than the relay will draw, I'd suggest 
measuring the resistance of the relay coil, put that value of resistance 
across the wall-wart, and check the voltage across the resistor.  Up to 14 volts 
should be fine.

In a message dated 10/21/2006 3:23:52 PM Central Daylight Time, 
revcom at wbsnet.org writes: 
> setting up my 51J4 to mute from my antenna changeover relay.  I was looking
> thru my junk box for a 12V wall wart to power the 51J4 relay and found
> something interesting that I can't explain...
> 
> Seems I have a bunch of these wallwarts that are labeled for 12VDC output. I
> noticed that some output 12VDC such as an old laptop wallwart. However, some
> others that are labeled as 12VDC actually output something like 20VDC when I
> measure it with my dmm. One example is a wallwart for a cordless phone. It
> is very small and the output says 12vdc 200ma.  It measures 20vdc on the
> dmm.  Why would this be? I get the same result on a couple of these
> wallwarts, so I don't think its a fluke.
> 
> Could it be because the wallwart is somehow expecting some loading? If I
> loaded this would it output 12vdc? I am afraid to put 20vdc onto the 51J4
> relay coil. Should I be afraid? Or if my theory of loading is correct, might
> the output go down to 12v when connected to the relay? Just a little afraid
> to try.
> 

Robert & Susan Downs - Houston
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