Some equipment from the 80s and 90s had these tiny 12 volt globes to light up meters, dials, etc. The globe had 2 wires coming out (it didn't screw in to a socket). I've found these things to be incredibly unreliable, and I'd like to replace some with LEDs of the same size and brightness.

Question: Do such LEDs exist? If so, what is the value of the series resistor to be used?

In the case of 2 or 3 globes, I'd like to put the replacement LEDs in series, to keep the current draw down - and only need one resistor.

In these cases what would the resistor values be? Also, what LED would you recommend?

Hi Robbbert
There should be available LED of a similar physical size that would replace those bulbs.
As you are only needing about 10mA to run a led, I would start of with about a 1k resistor
and adjust the value to get the required brightness similar to the bulbs you are replacing.
Having a quick look on ebay there are 5mm and 3mm round LEDs,
You could run them in series or parallel using a single resistor.

If the globes are the ones I am thinking of, a 3mm LED would be about the same size however you are not likely to match the colour temperature. If this isn't a concern then the rest just involves the changeover from globe to LED. If Norm's suggestion works, the job shouldn't cost more than a tenner.

A lot of the supermarkets do either quote current, or have data on the LED.'s they sell.

I've used LEDs from Xmas light strings to replace panel lights in ham and CB radios. The LEDs are roughly the same diameter of the old light bulbs. The Xmas light LEDs have inverse cone shapes molded into their plastic cases. This cone distributes the light roughly evenly, compared to regular LEDs that aim most of their light in one direction.

I'd try a resistor of 10K for a power supply of 12V. Modern LEDs don't need much current.

The trouble with LED's replacing those little incandescent globes is that the LED doesn't throw much light sideways and when it's used to illuminate a dial by being inserted at one end the results are often disappointing.
LED's are usually quite directional.
Sometimes you can fiddle with positioning of the LED and get an acceptable result.
Worth a try anyhow.

When you run a LED on AC the colour temp seems to go batty. A Red Led is bright red on a DC supply but more like an orange colour on AC which may be due to the fact that the LED is meant for DC use and on an AC supply it is only seeing half wave pulses so not being fully energised.

Lindsay

At the end of the day: It is a diode

I have used a short length of adhesive strip that has SMD leds-cut to length, has integrated resistors, 12volt approx. Ebay cheap.
It replaced a tiny fluro tube in back of a studio clock, worked well...might work for you.