G8MNY  > TECH     13.04.25 07:45z 59 Lines 2286 Bytes #174 (0) @ WW
BID : 30207_GB7CIP
Subj: Christmas Mains Light Chains
Path: ED1ZAC<ED1ZAC<GB7CIP
Sent: 250413/0737Z @:GB7CIP.#32.GBR.EURO #:30207 [Caterham Surrey GBR]
From: G8MNY@GB7CIP.#32.GBR.EURO
To  : TECH@WW

By G8MNY                                           (New Dec 06)
(8 Bit ASCII graphics use code page 437 or 850, Terminal Font)

If you are having problems with those plug/screw in Christmas fairy lights
after getting them out from last year here are some tips.

FINDING DUD LAMPS
Use a DIY metal/mains detector to show the mains field along a chain of lamps..
               ÚÄÄÄÄÄÄÄÄ¿
       Fuse    ³Detector³
       Lamp    ÀÄÄÄÄÄÄÄÄÙ      live   dead
LiveÄÄÄ(x)ÄÄÄÄ(x)ÄÄÄÄ(x)ÄÄÄÄ(x)ÄÄÄÄ( )ÄÄÄÄ(x)ÄÄÄÄ(x)ÄÄÄÄ(x)Ä¿
                                 dud lamp                   ³
NeutralÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ

Provided it is wired correctly & the live wire goes to the first safety lamp,
then the detector will fail when the LIVE electric field disappears at a dud
lamp.

SHORTED LAMPS
Normal chain lamps have shorting link around the oxidised internal lamp wires,
if the lamp sees too high a voltage such as when the filament blows the oxide
layer breaks down the link welds the lamp short. If too many lamps go short the
whole chain will blow in a few seconds, that is why you must have a fuse lamp!

SAFETY FUSE LAMPS
As shown above the 1st lamp in the live circuit should be a fuse bulb. These do
not have the shorting link, & they also have a thinner longer filament. They
are identified with a white frosting on them.

LAMP VOLTAGE
When swapping/changing lamps it is important to get the same current & voltage
lamp. This is easily worked out by counting the number of lamps in the chain
& dividing the supply volts by that. Often 20, 30 or 40 lamp sets are standard,
giving 6, 9 or 12V for 240V mains.

LIFETIME
Lamps run properly will last a long time (500 hours), for longer life, if you
can use more lamps than standard e.g. a 22 chain set instead of 20, may last
twice as long but 20% dimmer.

SAFETY
Do not put these light chains near metal objects like tinsel or metalized
Christmas trees as there is always a chance that bare wire contact can be made.

Also note lamps do get quite hot & any material used nearby must be flame
proof!

See my TECH buls on "LED Test Screwdriver". "Fairy Light Flasher" & "Night
Light Switch".


Why Don't U send an interesting bul?

73 De John, G8MNY @ GB7CIP


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