I'm looking for a couple of these to repair some (antique) equipment. They should be 1.5V, about 30mA and produce a relatively 'white' light at this current. Some Radio Shack 6V, 100mA bulbs draw approximately the correct current at 1.5V, but they are too reddish and dim to be of any use.
These are used in an old photographic light meter as a null indicator. LEDs won't work at this voltage level (too dim and no where near linear brightness vs voltage).
First Googling turns up some bulbs offered by Kit Kraft, for dollhouse use:
Stated as 1.5 - 3 volts, current draw not stated.
You could cannibalize a cheap LCD watch. They use tiny 1.5V bulbs to backlit the display.
Piotr
If you could add an opamp for voltage to current, you might be able to use a LED. Otherwise more shopping around, perhaps hobby model shops?
Grant.
Ebay #> 120598027723
Have to hack the cute lampshades off maybe? JC
or you could try
JC
On 7/29/2010 11:07 AM Paul Hovnanian P.E. spake thus:
Is that meter by any chance a Gossen? the type with two bulbs that light up equally bright when the dial is adjusted correctly? I had one of those when I was a kid. Luna Pro?
Try a hobby shop that caters to model railroaders (lots of other interesting stuff there too!)
Eg.
Best regards, Spehro Pefhany
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1.5v @ 40 ma. lamp (All Electronics):
Yes. One lamp is burned out. I measured the voltage and lamp current of the good one. I'll be replacing both of them (just to keep the differential circuit properly balanced).
Model train hobby shops carry all sorts of small lamps. Might give one of them a try.
Mark Z.
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