I can't seem to find a 9 V grain of wheat incandescent bulb anywhere. Looking for something small ( about 1/4"- 1/2" size), best with leads either radial or axial, but will settle for screw or bayonet connections. The application is for VU meter lighting in a large console, which I'm also rebuilding the metal frame (metalwork content).
cheers T.Alan
If worse comes to worse, use a
12 volt lamp with a 3.3 volt zener in series."Jim Stewart" wrote: If worse comes to worse, use a 12 volt lamp with a
3.3 volt zener in series. ^^^^^^^^^^^^^^^^^^^ Won't that add up to 15.3 volts?
These folks have filled some unusual requests for me...
Zeners subtract, not add.
Ah, no. That isn't the way it goes. The guy apparently has a 9V source and wants a bulb to run on that. A zener will take the 12V bulb and allow it to run on a 15V source.
-- Why isn't there an Ozone Hole at the NORTH Pole?
So he buys a 6V bulb! Next!
Start by trying a 12V bulb. It will run a bit yellow and not put out as much power but it will run for basically forever at that voltage. If you really want full brightness in a nice white light, take a 1.5V bulb and run a resistor and pair of diodes (in series) in parallel to the bulb to insure that the voltage doesn't go too high. A 3V bulb is avialble also but aren't as common.
-- Why isn't there an Ozone Hole at the NORTH Pole?
I think he meant use a 6 volt lamp....
But a resistor might be even cheaper than a zener.
Jeff
How do you know you need a 9 volt lamp? Is this specified or are you assuming this from the voltage you are measuring? It could well be that the original design was to use a 12 volt lamp on 9 volts to give a softer light and to give an extended bulb life.
Chuck P.
Why don't you replace it with a white LED and a resistor?
Best regards, Spehro Pefhany
If you're tearing it apart anyway I'd suggest converting it to LED lighting so you don't have to tear it apart again in the future to replace burnt out bulbs. White LED have become quite cheap (~$1-$2 depending on output) so even if you're talking a 32 input board the hassle of having to replace them in the future outweighs the cost difference. It also gives you the option of using different colors if you want, say one color for inputs another for mains another for subs...
Pete C.
"T.Alan Kraus" wrote:
You're right. Typed before I thought.
You're right. Typed before I thought.
I think the LED suggestions are good. But if you must use grain of wheat/rice lamps, model railroaders use these by the bushel, at various voltages, usually lower than 9V, but mebbe also
9-12V. Connect a few in series for your voltage, and you'll have a more uniform lighting.
Streamlight TL-3 Replacement Bulb
Maybe a 5-cell MagLite bulb; may need a diode in series. If it's running on AC a pair of diodes in parallel with one pointing in each direction. This would be rather bright and might draw too much current.
He has only 9 volt source. Zener will subtract 3.3 from that so he can use
6 volt lamp. That is assuming the his source is DC.Regards,
Boris Mohar
Got Knock? - see: Viatrack Printed Circuit Designs (among other things)
Just put a 'regular' 12v Grain of Wheat one in, it'll be a bit dimmer but it will never burn out ! Well, almost never....... If you're ambitious, you could use a few of those nice white LEDs now on the market and they won't butn out either.... jay
T.Alan Kraus wrote: The
Is there a possibility that a 12V bulb was used? VU meters are usually pretty dim. What kind of board is it?
Kevin Gallimore
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