A very cheap solution would be to put a resistor in series with the
lights and an SPST switch in parrallel with the resistor (to short it
out). You need to figure out the resistance on the chain of bulbs, find
a suitable similar resistance (for 1/2 power... more for less light,
etc) Power rating needs to be figured out as well. For 1/2 power, it
should match the total of all the lights... less if you raise the
resistance.

THis doesn't give you the variable resistance but it is a couple dollar
solution that may solve the problem.



Rusty wrote:
The Blue Sea dimmers are about two by three inches and about one inch thick.
They have five wires coming out one end. These wires go to 1) Ground, 2)
Power, 3) Bright, 4) Dim, 5) Light. The wires themselves are labeled for
their use. The switch you use to control the dimmer is designated (ON) OFF
(ON).

(ON) means 'Momentary On' so the switch returns with a spring when you press
on the top or the bottom and returns to the middle OFF position when you
release it. Switches like this connect a circuit from the center connection
to the bottom connection when you push on the top of the switch. They
connect the center position to the top connection when you push on the
bottom of the switch. Note: This is backwards to what you might expect.

To wire the dimmer you connect the 'Ground' lead to DC negative, the 'Power'
lead, and the center connection on the switch, to DC positive. The 'Bright'
lead connects to the bottom of the switch and the 'Dim' lead connects to the
top of the switch. The 'Light' lead goes to your light bulbs and of course
you connect the other end of each light bulb to DC negative. Don't forget
that DC positive lead to the center connection of the switch, it won't work
without it.

Now when you push on the top of the switch the lights will get brighter and
when you push on the bottom of the switch they will get dimmer. Another good
feature is the dimmer will 'remember' the last setting and return to it if
you turn off the power and later turn it back on again.

These dimmer units are available in 2 amp, 5 amp, and 10 amp versions. They
can also be used to control the speed of DC powered fans.

If you just want a simple rotary knob dimmer, Cole Hersee makes two
different models also available through West Marine and several other
suppliers. These, and the low amp Blue Sea system, all run about the same
price.

I answer to Johnhh's question, home dimmer switches haven't been made with
variable power resistors in more than thirty years.

Rusty O


"Johnhh" wrote in message
...

I guess I just always assumed they were just variable resistors. There I
go assuming again--it gets me every time. Were they ever made with
variable resistors?

How do the Blue Sea one's work?