Topband: 12 volt relays
Missouri Guy, N0TT
n0tt1 at juno.com
Sat Apr 7 21:39:16 EDT 2007
> That is an easy solution. But I think you missed the point that I
> was
> attempting to keep my entire system powered by a single 12 to13.8V
> storage battery for emergency purposes. Then the task is not quite
> so
> direct. I think the thread was also useful because it makes
> potential
> users of a seemingly acceptable circuit aware that it doesn't
> perform
> to the level expected.
Thomas,
I got into the thread a little late....It's been awhile since I've
looked at the circuit I've used which operates a 24-v relay
from 12v, but as I remember it and FWIW, I use a DPDT
switch and charge up two capacitors in parallel, then when
I want to switch the relay, the two caps are connected in series
by the switch which then pulls up the relay. I have a "keep alive"
resistor that keeps the relay operated for as long as needed. Obviously
it's not a circuit that would be any good for fast "QSK" switching.
I used it to remotely switch a matching circuit on my "Dakota Special"
vertical.
One of the circuits I saw referred to on the net that used a transistor
was a nice piece of work...very clever design.
>
> As I mentioned in one of my earlier post, I am pursuing the boost
> regulator approach and now have a couple of MC33063AP ICs on order.
>
> I'll provide the schematic to those who have expressed interest in a
>
> circuit after I've had a chance to build it on the bench.
I'd like to see that.
73,
Charlie, N0TT
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