Re: Q: Reducing 20VDC Line to 12VDC

On Nov 15, 8:40 pm, Gott Lieb? <r...@xxxxxxxxxxxxx> wrote:
I am trying to replace the missing topper on a Rescue 911. The line
that feeds it is 20VDC. PBR no longer stocks OEM replacement units.
The similar replacements closest in voltage are either 12VDC or 24VDC,
and the 12VDC units are more prevalent due to automotive use. I picked
up a 12v unit, and the wattage is spec'd on the bulb, (which I found
odd), but I have no clue what the beacon motor draws.

I was hoping to put a 5W - 10w power resistor, (with an unknown
resistance at this point), on the line to solve the voltage difference.
This is how Gottlieb, (and WMS for that matter), typically handled the
power to their flasher lamp circuits. The flasher circuits on GTB's
were on the +24VDC solenoid buss with power resistors, (8 ohm 5w wire
wound), placed in series prior to the lamps, (#67's - 13.5v).

The only thing I'm concerned about is that a flasher lamp is an entirely
different circuit than a lamp with constant illumination, plus a small
motor in the mix.

Am I off base here thinking that I can get away with just a resistor
tied in series in the circuit to accommodate the difference in voltage?

Jim
CARGPB #35



ch...@xxxxxxxxxxx wrote:
Jim,

I have no idea. But, I'm interested in what you are trying to do. Can
you describe it?
--
Chris Hibler - CARGPB #31
www.Team-EM.com

On Nov 15, 8:40 pm, Gott Lieb? <r...@xxxxxxxxxxxxx> wrote:

Is there a method to reduce a 20VDC line for a 12VDC fixture without
knowing exactly what the wattage or amperage draw of the fixture is?

Jim
CARGPB #35- Hide quoted text -

- Show quoted text -

I think that a 5 ohm 5W or 10W resistor will do the trick. These
things are not critical.
.

Relevant Pages

  • Re: LEDs
    ... > provide a fixed current and voltage? ... as long as the voltage drop across the resistor is large. ... these circuits use transistors and integrated ... They still dissipate the power due to the extra supply voltage as ...
    (sci.electronics.basics)
  • Re: Whats the, um, aim in electronics?
    ... Generally speaking, when it comes to electric circuits, is it fair to ... A resistor resists the flow of current. ... circuits do not always work by manipulating current; ... constant voltage). ...
    (sci.electronics.basics)
  • Re: "Reverse engineering" burnt resistors
    ... If you don't know the voltage across the resistor, or the current, ... For most circuits you need to be no more than 20% off. ... Multiply one wild ...
    (sci.electronics.repair)
  • Re: P2B-DS and generic slotkets
    ... The slockets are labeled "Cpu Card ... processors are requesting 2.0 volts instead of 1.65 volts. ... If R3 is a 56 ohm resistor, ... With regard to the voltage being requested, ...
    (alt.comp.periphs.mainboard.asus)
  • Re: Einsteins Doppler equation wrong?
    ... the voltage is zero, i.e dE/dt is at its greatest, and ceases when the ... short circuit. ... :>: consisted of a connector with a small resistor tying the core ... :>: Without the terminator, the thinnet cable spits back echoes into ...
    (sci.physics.relativity)
Loading