It's old technology but it might be worth trying a neon lamp, which may not give exactly the colour you need, but it should last a long, long time and consume very little power. ( mains voltage so may not be safe, depending on location.)

Rod

In my experience LED's always lasted a lot longer than incandescent lamps. I would be thinking along the lines of a standard LED (not high brightness) and maybe use a translucent shade or 'envelope' to decrease the brightness more, if required.

I expect some of the electronics guys here could describe a good solution, perhaps with a dimmer circuit.

Ed.

Halogens are designed to run at a particular voltage and too many or too few volts reduce their lives.They also run hot and are inefficient. An ordinary incandescent bulb like a car sidelight would be better or perhaps a LED on a suitable dimmer.

Most lamps last longer when run dim and switching on and off is what bumps most of them off. An under run bulb that's never switched off could last for decades.

Dave

+1 on using an LED, of course you should probably look in Digikey or other electronics supply places to get one with high reliability and longest possible life. I have seen the better ones listed in such places as 50,000 hour , or 5.7 years continuous operation guaranteed life. Only a dollar or two more than the cheapies. Using a cheapie would definitely be a transgression in this application.

Anyway as to brightness there is no reason you could not use a dark plastic filter sheet or two over/around the LED to block some of the emitted light to dim it, while letting it run at design rated current for best life. In this case it may be needed to hide one's light under a (semi transparent) bushel. (sorry)

Any ex phone charger wall wart power supply would work for powering it, if output V and I were what the LED required. Just food for thought.

You could use an LED and a circuit from this website to control the brightness :

**LINK**

Stuart

With all the 'soft' fabrics you describe about there is no way any 'high energy' filament lamp should be used.

LED way to go.

Why can't an old-style incandescent light bulb last for a century's continuous use? Some can. The explanation may surprise you. See "The Light Bulb Conspiracy – Extended Version" **LINK**

Don't worry, it's not loony conspiracy theory nonsense, but a sensible documentary. Unfortunately, it may raise your blood pressure to dangerous levels. It explains a lot about why much of what we buy fails far too early.

Edited By Kiwi Bloke on 25/07/2020 11:20:06

Filament type Christmas lights are designed to be 'over-run', operating at a very high temperature which gives great light output, a brilliant sparkly effect, and a short life ensuring a good trade in replacements. When the traditional 'olive cone' bulbs became difficult to get I sacrificed one twelve-light string and used it to extend all the others to 15 lights. Since then – over ten years ago – I have had almost no failures, and having laid in a stock of spare bulbs when I could still get them, I have a lifetime supply which will keep my heirs and successors in fairy lights for generations to come, even though they are no longer made.

The 'more recent' (last fifty years?) olive cone lamps have an internal device which short circuits the bulb when it fails, which makes it easy to identify a dead one in the series string. Previously one had to take out and test each bulb individually which took for ever. However, it does mean that they are seriously unsuitable for single or parallel use, as they would short-circuit the power supply on failure.

Personally I would favour a suitable, under-run filament bulb for this application, because it gives a more pleasant and omni-directional light than the alternatives.

George B.

A door bell transformer should fit the requirements.

John

Sod is correct on halogens.

For a simple solution I suggest a LED rear red sidelight bulb either run off a lower voltage or with a series resistance to reduce the brightness. Reducung he brightness in this way will increase the life significantly.
Personally I'd make up a lamp of several individual 5mm LEDs and resistors, running them well below rating.
A norml mains transformer and rectifier will be more reliable than a switchmode, power supply. Again over rate it e.g a 15VA transformer for "5W" LED sidelight.

Robert G8RPI.

Edited By Robert Atkinson 2 on 25/07/2020 16:30:11

the 12v red LEDs I have consist of 5 minicards each containing 2 modules comprising 3 v small Leds and current limiting resistor – these minicards arranged arranged around the axis of the bulb topped by another card also containing 3 3-leds etc all fed in parallel from the 12v – the fixing base being a small bayonet – height above the base 30mm (the small bayonet is abt 20mm deep – guess arranged thus to provide a fair amount of redundancy

I take it this is an Alarm in Operation warning and not a fault on the circuit warning ?

Emgee