On Dec 9, 6:20*pm, Jeff Wisnia wrote:
hr(bob) wrote:
On Dec 8, 7:47 pm, (Don Klipstein) wrote:

In communications, Jeff

Wisnia wrote:

Just what is in the "shunt" built into series string decorative lamp
bulbs which takes over when the filament opens?

Is it something like a PTC thermistor which heats up and melts some
powdered metal into a permanent short?

My curious mind wants to know.

*As it turns out, I don't really know what those things are made of.

*I would guess the whole string needs some sort of fuse - eventually all
of the shorting devices will do so.

- Don Klipstein )

The fuse in the plug is both for the light string itself, and to
protect against too many strings being plugged one after another *into
previous strings and overloading the wires in the string closest to
the power source.

I believe you must be writing about parallel strings with 120 volt bulbs
in them. I was asking about series strings, and I don't think you can
plug another string into those, can you?

Jeff

--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10^12 furlongs per fortnight.- Hide quoted text -

- Show quoted text -

I have in my possession several 100 light sets, 2 50-light sets in
series, with a male plug for providing power and a female plug at the
other end of the 100 lights to plug in another string, and so forth.
Eventually there is too much current draw and one or both of the fuses
in the first circuit will blow. Frequently there will be a label on
such types of sets saying how many strings can be connected in
series. Take a look at some of the lights in the stores right now.