Author Topic: Christmas mini lights (filament/incandescent, not LED) - question about voltages  (Read 4466 times)

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Offline Zbyszek

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I will disagree with some statements about how robust are LED lamps. For many years I was using for outside decoration incandescent bulb. 1.) If snow covered them then next day lamps melted it and appeared again. LED is cool so was lost buried by snow. This can be fixed shaking off snow from the branches, but still 1:0 for incandescent. 2.) Incandescent lamps had some kind of non corrosive wires contrary to LED which has iron wires . After one (max two) seasons they are rusted and not working anymore. 2:0
 

Online Brumby

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The first set I remember had a string of globes rated for 17V.  They had a screw base and, from memory, were about 5cm or so long (it's been a while).  These were in the days of, if one globe failed, the whole string went dark.  Chasing down the faulty globe was THE Christmas ritual nobody liked (I didn't buy my first multimeter until some years later).

I seem to recall from my childhood that some of the strings had special sockets that shorted out if you removed the bulb. So finding a faulty bulb just involved removing each bulb in turn until the string came back on. Also, if you had a faulty bulb on Christmas Day with no spares available, you could just remove the faulty bulb until you could obtain a replacement.

There was no such behaviour from those lights.  (It was Australia pre 1970)
 

Offline SolderSuckerTopic starter

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A totally off the wall suggestion, which might look really ugly!... https://www.ebay.co.uk/itm/111023835999

That's actually a nice find, I've been hoping that somebody would produce coloured caps for LED lights. Thanks for the very useful link, it's giving me some more ideas and I see via an Ebay search that there are also caps for 5mm LEDs, etc. For example:

https://www.ebay.co.uk/itm/374214367617

« Last Edit: October 29, 2023, 09:52:30 am by SolderSucker »
 

Offline SolderSuckerTopic starter

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We have been driving our retro incandescent Xmas lights with a dimmer for many seasons. Running at 80% has little impact on visual brightness but, reduces heating and extends the lifespan of the strings. Also, a dimmer provides a soft start, treating the ageing filaments with care. I have zero idea if spare bulbs even exist. One string is so retro, the bulbs are LES fitting.

Image. I cannot recommend this dimmer as I do not own one but, such plugin devices exist for UK sockets. This one is quoted at 300W. Be sure to downrate the fuse in your festive light string's plug to 3 Amps. I should add that a dimmer is not ever compatible with mini LED transformers - they are buck converters and will likely buzz very loudly if dimmed.

Thanks, I see the one that you provided the image of:

https://www.amazon.co.uk/Mercury-DMR-1WHT-Plugin-Dimmer-Switch/dp/B000LAU04K/

I think I'll give it a go. Noted about changing the fuse in each string's plug to 3 amps.

One question though - I plan to plug three strings (each consisting of 100 filament bulbs) into a multiway adapter and then that into the dimmer. Any potential problems there? Each string is rated at 33 watts, the linked adapter is 300 watts so should be fine.
« Last Edit: October 29, 2023, 09:50:18 am by SolderSucker »
 

Offline themadhippy

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Quote
Or use a diode,
The flicker might be a problem for some,but for those of us who put fluorescent  starters in series with there lights its another flashing  effect
 

Offline IanB

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but for those of us who put fluorescent  starters in series with there lights its another flashing  effect

There are people other than you who do that?
 

Offline themadhippy

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There are people other than you who do that?
Yep,bucket loads,was a very common method of achieving a fire lighting effect in theatre and film
 

Offline AndyBeez

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One question though - I plan to plug three strings (each consisting of 100 filament bulbs) into a multiway adapter and then that into the dimmer. Any potential problems there? Each string is rated at 33 watts, the linked adapter is 300 watts so should be fine.

There might be a sight imbalance when cold starting as one string is likely to have a series resistance lower than the other two. And one string might be brighter just because of the bulb rating, but in theory, it work out okay. Let us know how you get on.
 

Offline soldar

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All my posts are made with 100% recycled electrons and bare traces of grey matter.
 

Offline RJSV

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   I enjoyed experimenting, with individual mini-lamps, although I didn't consider the issue of self-shorting types...(Yikes!).
   One curious phenomina that occured was a variation of lamp 'HALO' visual trick;  Somebody had built a room decoration where a little red bulb was positioned precisely in front of a blue mini-bulb.  The trick effect was that the red mini-lamps appeared to have a BLUE aura!  You had to move your head around a bit, to discover what was going on.

Wouldn't hurt to downgrade the volts, some, using 2.0 volts vs. 2.4 standard.  Don't forget that's AC rms, in those 'old days' (1992).  I think the current was somewhere around 40 to 100 mA each, which is a fairly fast drain, on small battery...certainly won't last more than one night.
   Some guitar effects, such as Fender amp tremolo have used the softer response of a filament lamp / with LDR (light dependant resistor), for modulating volume.
 
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Offline andy2000

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Or use a diode, trivial to seal up in heat shrink.

I've been doing this for years for incandescent light sets which are too bright.  It doesn't cause noticeable flicker to my eyes, and I'm very sensitive to the flicker of most LED light sets.  One of the main reason I don't use LED Christmas lights is because almost all of them look like strobe lights to me.
 

Offline lezginka_kabardinka

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Why bother with them. They regularly use different/proprietary bulbs so it's always been a pain to use them. They also had a nasty habbit of catching trees on fire etc.

This is one of those times were it's really nice to have LED.

Just because LEDs are the latest obsession, plastered in, and on EVERYTHING, doesn't make them "better" for EVERYTHING. He wants filament, and I am with him on this; they are vastly superior.
 
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Offline Sredni

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Incandescent camp here.
The atmosphere is unique. I mostly use strings of 10 and 20 bulbs, rated for 24V and 12V. When my country moved from 220V to 230V I had to endure "The Great Burning" due to the reduced lifespan when running at a higher voltage.
Being lazy, I simply went through dozens of strings, at least four per season, until I had enough and put a diode in series with them. 'Half' voltage, quarter power they became eternal. And in my eyes, they even look better.

There are different ways to reduce the voltage:
- single diode
- two series of 10-20 diodes in parallel, with opposing orientation
- series capacitor
- a 12 to 24 V transformer to wire in series so that the voltage is subtracted from the mains voltage
- a full blown variac (but that's overkill)

Or even adding 3-4 extra lamps to the series (but they need to come from the same batch)

To the OP, my advice is to power a single bulb with a variable voltage source and record the current. Once you reach the right brightness you should find the operating voltage (in case it's one of those string where multiple series are in parallel).
All instruments lie. Usually on the bench.
 

Offline IanB

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There are different ways to reduce the voltage:
- single diode
- two series of 10-20 diodes in parallel, with opposing orientation
- series capacitor
- a 12 to 24 V transformer to wire in series so that the voltage is subtracted from the mains voltage
- a full blown variac (but that's overkill)

Or a simple phase angle lamp dimmer? These are simple, commodity items, plug and play.
 

Offline Sredni

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There are different ways to reduce the voltage:
- single diode
- two series of 10-20 diodes in parallel, with opposing orientation
- series capacitor
- a 12 to 24 V transformer to wire in series so that the voltage is subtracted from the mains voltage
- a full blown variac (but that's overkill)

Or a simple phase angle lamp dimmer? These are simple, commodity items, plug and play.

The ones I have always used for my light fixtures had a minimum power requirement of a out 100W. Iirc they buzzed when used at lower powers, or maybe they just didn't start. I never bothered to search for a more adequate product.
All instruments lie. Usually on the bench.
 

Offline IanB

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The ones I have always used for my light fixtures had a minimum power requirement of a out 100W. Iirc they buzzed when used at lower powers, or maybe they just didn't start. I never bothered to search for a more adequate product.

That's odd. I have never encountered one with such a high minimum power requirement.
 

Offline Zero999

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The ones I have always used for my light fixtures had a minimum power requirement of a out 100W. Iirc they buzzed when used at lower powers, or maybe they just didn't start. I never bothered to search for a more adequate product.

That's odd. I have never encountered one with such a high minimum power requirement.
I would expect the minimum power requirement would be higher on 230V, than 120V, since the power is double, given the same current. I don't recall a dimmer with a minimum load of 100W though. 40W is most common.
 

Offline Sredni

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Just checked it: they are rated for loads with power comprised between 100W and 500W.
These were bought more than 15 years ago.
There are newer versions that go from 40W up (to 200W max), and even some with a minimum requirement of 10W.

I need to refresh the theory on how to design these things...
« Last Edit: November 01, 2023, 09:20:55 pm by Sredni »
All instruments lie. Usually on the bench.
 


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