Grain-of-wheat bulbs
Paul Hovnanian P.E.
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).
--
Paul Hovnanian pa...@hovnanian.com
----------------------------------------------------------------------
Have gnu, will travel.
Dave Platt
Paul Hovnanian P.E. <pa...@hovnanian.com> wrote:
>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: http://www.kitkraft.biz/product.php?productid=5582
Stated as 1.5 - 3 volts, current draw not stated.
--
Dave Platt <dpl...@radagast.org> AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
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Piotr Piatek
>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.
You could cannibalize a cheap LCD watch. They use tiny 1.5V bulbs to
backlit the display.
Piotr
Grant
>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).
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.
Archon
> 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).
>
Ebay #> 120598027723
Have to hack the cute lampshades off maybe?
JC
Archon
David Nebenzahl
> 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).
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?
--
The fashion in killing has an insouciant, flirty style this spring,
with the flaunting of well-defined muscle, wrapped in flags.
- Comment from an article on Antiwar.com (http://antiwar.com)
Spehro Pefhany
<pa...@hovnanian.com> wrote:
>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).
Try a hobby shop that caters to model railroaders (lots of other
interesting stuff there too!)
Eg.
http://www.grsmicroliting.com/eshop/index.html?target=dept_5.html&lang=en-us
"1.5V and 3.0V Super GOR Bulbs"
Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
sp...@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
J. Todd
pa...@hovnanian.com says...
> 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).
>
>
--- news://freenews.netfront.net/ - complaints: ne...@netfront.net ---
Sofa Slug
> 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).
>
1.5v @ 40 ma. lamp (All Electronics): http://tinyurl.com/24khy9l
...they also carry a 3v @ 55 ma. version.
Paul Hovnanian P.E.
>
> On 7/29/2010 11:07 AM Paul Hovnanian P.E. spake thus:
>
> > 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).
>
> 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?
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).
--
Paul Hovnanian mailto:Pa...@Hovnanian.com
------------------------------------------------------------------
c (velocity of light in a vacuum) = 1.8x10^12 furlongs per fortnight
Mark Zacharias
news:4C68AE9C...@Hovnanian.com...
Model train hobby shops carry all sorts of small lamps. Might give one of
them a try.
Mark Z.