UK Vintage Radio Repair and Restoration Discussion Forum

UK Vintage Radio Repair and Restoration Discussion Forum (https://www.vintage-radio.net/forum/index.php)
-   Where To Get Sets and Parts (https://www.vintage-radio.net/forum/forumdisplay.php?f=19)
-   -   Lamp Limiter Bulbs (https://www.vintage-radio.net/forum/showthread.php?t=143469)

Guest 29th Jan 2018 9:47 am

Lamp Limiter Bulbs
 
Poundland are doing decorative filament bulbs (for a quid!) should suit a lamp limiter nicely. As they are screw in a few in parallel could be switched in and out easily.

G6Tanuki 30th Jan 2018 8:00 pm

Re: Lamp Limiter Bulbs
 
Also, my local B&M has Eveready-brand ES halogens in packs-of-three on special-offer at the moment.

hamid_1 30th Jan 2018 10:41 pm

Re: Lamp Limiter Bulbs
 
2 Attachment(s)
The "Antique" filament bulbs are quite interesting in their own right. They are made to look like early 20th century light bulbs - some even have a pip on top. Various styles are available with BC or ES caps. Poundland have been selling them for £1 though they're not always in stock. Other shops have them too, but usually more expensive.

Here's one I bought from Poundland last year. It's a 60 watt ES "Antique" pip-top bulb - I also bought a BC version of the same design. It uses a real filament, but despite being rated at 60 watts, the light output is fairly low. I'd say it's more like a 25w traditional bulb. The glass has a yellow tint which probably reduces the brightness somewhat. It does consume around 60 watts as measured by a Maplin power meter.

As well as being useful for lamp limiters, these bulbs could be used in a display of vintage radio and electrical items. They certainly look vintage even though they're not.

jonnybear 4th Feb 2018 7:00 pm

Re: Lamp Limiter Bulbs
 
Like the old barretter tubes of bygone days, perhaps if they do not give much light they could be used as a replacement.
John

Ed_Dinning 4th Feb 2018 10:09 pm

Re: Lamp Limiter Bulbs
 
Hi Gents, if you want to try it as a Barretter take a plot of volts and amps and look for a flat region on the graph (constant current). To be fully effective it needs to be hydrogen filled for good thermal conductivity.

Ed

JHGibson 5th Feb 2018 9:27 pm

Re: Lamp Limiter Bulbs
 
Those golden glow 'antique"light bulbs have carbon filaments which have a negative temp coefficient. That is when cold they have a high resistance which falls as the filament heats up. They would make a good barretter type dropper resistor which would be kind to the valve heaters and dial lamps. You have to choose one with the appropriate hot resistance.
John.

broadgage 9th Feb 2018 12:47 am

Re: Lamp Limiter Bulbs
 
I think that you are mistaken in saying that these lamps have carbon filaments.
Almost all these "vintage style" but recently manufactured lamps have a tungsten filament that is a reasonable copy of the early types of tungsten filament lamp, used before coiled filaments.

Many vendors on ebay and elsewhere describe them as "carbon filament" but they are wrong ! If in any doubt, a very simple test will prove this.

Measure or calculate the hot resistance when the lamp is lit at about nominal voltage.
Now measure the cold resistance with a test meter.

In the very likely event that you have found a true carbon filament lamp, then the cold resistance will be higher than the hot resistance.

In the much more likely event that you have a vintage style lamp with a metal filament, then the hot resistance will be much higher than the cold resistance.

True carbon filament lamps of recent manufacture are now very hard to find.

"Vintage type" but recently manufactured tungsten filament lamps are very popular and widely available.

LED copies of the metal filament types are also widely available and are IMHO rather attractive, but no good for a lamp limiter.
LED copies of carbon lamps also exist but are less common, again attractive in some situations but also no good as a lamp limiter.


All times are GMT +1. The time now is 6:00 pm.

Powered by vBulletin®
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Copyright ©2002 - 2023, Paul Stenning.