At 01:46 PM 10/27/97 -0600, you wrote:
>
>Well, not quite. The reason that house-type dimmers can be made
>so cheaply is due to the use of AC. Neither triacs nor SCRs work with
>DC, unless it is pulsating DC. To make this kind of dimmer for
>your dash you need a timing circuit, power switchers, SCR and a gating
>circuit. It would be efficient (fairly low heat) but complex. I just
>jumper my dash dimmer out of the circuit. The instruments are barely
>legible in that case and I can't imagine wanting them lit more
>dimly....
You're right of course. I was thinking ahead while I typed and
inadvertantly typed my thoughts (!?)
As I posted to the list as soon as I thought a bit about what I'd typed I
meant a power transistor. While driving this afternoon it occured to me
that replacing all the dash lamps with the 7.5V jobs from RS and installing
a transistor controlled dimmer circuit, the dash lamps could be controlled
from dark to very bright. The dash dimmer could be replaced with a "cheap as
dirt" pot and the stock knob stuck onto the shaft for original appearance.
Cheers,
Ross MacPherson
1947 MG-TC 3528
1966 MGB-GT
|