Re: Fitting a relay.

In article <44935c8d$0$950$ed2619ec@xxxxxxxxxxxxxxxxxxxxxxxxxx>,
Mike G <metier@xxxxxxxxxxx> wrote:
Yup - that's fine assuming the extra load of the relay coil doesn't
upset the warning system. Trouble is a relay will slow down the LEDs
coming on which is said to be a safety factor since they normally
light faster than incandescent. You could, of course, use a transistor
to switch the LEDs - this would switch instantly and not draw
significant current from the stop light circuit.

Thanks Dave. Looks like the relay I have draws about 80 mA. If this does
trigger the warning system, by suggesting using a transistor, would that
be the same as a solid state relay? Something like the 6 series shown
here.

http://snipurl.com/rvxb

Might be - but my PDF reader says this needs a password. ;-(

Which only needs 16 mA @ 30 VDC, or are you thinking of something made
up using a transistor, plus a few other bits on a bit of Vero board? You
can tell I'm a bit lost when it comes to really complicated electronics.

If you use a Darlington pair you can set the input current to far less
than that - although you have to be careful about spurious triggering if
the input is too sensitive. But mounting it close to one of the brake
lights should stop any possibility of this - although you can also use a
parallel resistor on the input to set the trigger current.

It would be easy to build one inside a standard relay - the older type
with the metal case which can be removed.

If you know the load of the LEDs, I could probably recommend the bits
which will cost no more than a ordinary relay.

--
*If love is blind, why is lingerie so popular? *

Dave Plowman dave@xxxxxxxxxxxxxxx London SW
To e-mail, change noise into sound.
.

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