Old miniature incandescent bulb size identification

[justheretoask]

I've found a classic new old stock flashlight that I'm rather fond of, but it uses incandescent globes, though I was hoping to be able to get some drop-in replacements so I could convert it to LED.

The only thing is, I'm not familiar with what type of globe size I'd need to look for (or even if a LED equivalent exists).

The flashlights are some classic Duracell keyring lights that use 1 x AA, (so I'd assume the voltage would have to be rated at 1.5v?)

And the oldschool incandescent globes they use:

Any ideas what this size is, or if a LED replacement can be sourced?

 

[HarryN]

The typical white LED needs ~ 3 volts to run.

So to do that electronically using the same battery ( 1.5 ish volts) requires a small circuit that boosts the voltage in a controlled way.

The other options are to find a battery that fits in there with a higher voltage.

A local CPF buddy helped me bore out a light similar to that, so we could fit a CR2 or CR123 battery inside - can't remember while one.

Then we added a small resistor to moderate the current flow to match the LED needs.

___________

If you are willing to accept an orange / red led color, those operate on somewhat lower voltage and "might" work with an energizer Li version of the AAs.

That used to be a super common bulb - sold everywhere, even in gas stations - but will need to think about the details.

They were sold by "1 cell, 2 cells, 4 cells" more than by size.

 

[HarryN]

Have you tried just doing an internet search for led replacement flashlight bulbs ?

 

[justheretoask]

The typical white LED needs ~ 3 volts to run.

So to do that electronically using the same battery ( 1.5 ish volts) requires a small circuit that boosts the voltage in a controlled way.

The other options are to find a battery that fits in there with a higher voltage.

A local CPF buddy helped me bore out a light similar to that, so we could fit a CR2 or CR123 battery inside - can't remember while one.

Then we added a small resistor to moderate the current flow to match the LED needs.

___________

If you are willing to accept an orange / red led color, those operate on somewhat lower voltage and "might" work with an energizer Li version of the AAs.

That used to be a super common bulb - sold everywhere, even in gas stations - but will need to think about the details.

They were sold by "1 cell, 2 cells, 4 cells" more than by size.

I have quite a few 1.5v LED flashlights that are quite powerful, so I guess I'd assumed that there would be something to replace the one in my post.

As for doing an internet search, I have had a look around, but the issue is that I wasn't sure what size/type the bulb is. I'm not really an expert with bulbs/bases.

 

[louie]

It looks like a midget flange base 1-3/4. Does it fit these dimensions? I only see them down to 2.5 volts, but that may be what they used. There are no markings on the lamps if you look very closely?

 

[nightshade]

Miniature Lamp Drawings & Specifications

Bulbs are described by a letter indicating shape and a number that is an approximation of diameter expressed in eighths of an inch.

www.rfcafe.com

OP, great user name 👍
Agree with Louie on T1.75.
You might be able to find NOS of those in a few places.
Some mini incans are becoming harder to find than rocking horse poo 😃

 

[snakebite]

I would gut a burned out bulb and install a 5mm led and resistor.
Something like a warm yuji.
Then run it with a 14500 li ion

 

[louie]

It might be like a 331 lamp:

331 - T1 3/4 Bulbs

normanlamps.com

I'm not aware of drop-in LEDs to replace a single cell incandescent T1-3/4, but I haven't looked. The problem, as mentioned, is that good white LEDs need more like 3 volts, so extra circuitry is needed, which is hard to fit in such small base. Larger torch lamps have LED dropins for sure.

Thus, you see recommendations for modifications if you want to go LED. You would have to decide if modifications or custom work is what you want to do.

 

[justheretoask]

Thanks so much for the suggestions guys! I'll take a look around.

 

[Henk4U2]

How about this: https://www.grainger.com/category/l...e-miniature-light-bulbs-lamps?categoryIndex=2