Making a Xmas tree light bulb tester

[W. eWatson]

I understand their our tree light testers that allow one to slip a bulb
into a hole, and an led will tell you if its defective. I found one
something like that on Amazon, but it's pretty pricey. They may be
called proximity testers. Can one be made easily?

 

[JeffM]

W. eWatson wrote:

tree light testers
that allow one to slip a bulb into a hole,

Pop out a bulb from one of your strings and look at the base.

Image a female connector that will quickly/easily mate with that.
(You could also use a socket from an old cast-off string,
but that would probably be more slow/futzy.)

defective.

Something that hasn't been mentioned in your previous thread

is the *advancement* in series-string Xmas lighting
that has been around for decades:

Imagine a pigtail made of 2 wires,
lightly-insulated and wrapped around each other.
Now imagine that they are inside a bulb,
one wire connected to each end of the filament.
When the filament burns out (opens),
ALL of the line voltage appears across that low-voltage capacitor
and its dielectric gets punched-through.
(This assumes that no other filament simultaneously burns out.)
The 2 wires now short together, bridging the bad bulb,
allowing the remaining lamps in the series string to continue to
light.

If you allow TOO MANY bulbs to do this,
then you will soon get a lot more than ~2.5 volts across each bulb
and life for the remaining bulbs will be reduced significantly.
REPLACE THE BAD BULBS **AS SOON AS POSSIBLE**.

Considering this advancement in technology,
a bulb tester now has to check for both an open and a short.
An easy-to-build tester that would cost nearly nothing
would have enough batteries / power supply voltage
to light a ~2.5V bulb with a ~1.7V LED in series,
and has a resistor as a voltage drop in case the bulb is shorted.

All that said, many light strings go dark
because of crappy design, materials, and workmanship.

I found one something like that on Amazon, but it's pretty pricey.

This sounds completely different from the "hole" thing

that you previously mentioned.
Bookmarking items you have found
and linking to those in posts is useful.

They may be called proximity testers.

Those gizmos look for an electric field *near* a conductor.

Can one be made easily?

If you have to ask the question, the answer is NO.

 

[Jasen Betts]

On 2011-12-16, W. eWatson <wolftracks@invalid.com> wrote:

I understand their our tree light testers that allow one to slip a bulb
into a hole, and an led will tell you if its defective. I found one
something like that on Amazon, but it's pretty pricey. They may be
called proximity testers. Can one be made easily?

audio amplifier with capacitive probes,
when the string powered there will be an increased
electic field level in the vacitinity of an open-circuit failed bulb.
and reduced field near the working bulbs.


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[Michael A. Terrell]

Jasen Betts wrote:

On 2011-12-16, W. eWatson <wolftracks@invalid.com> wrote:
I understand their our tree light testers that allow one to slip a bulb
into a hole, and an led will tell you if its defective. I found one
something like that on Amazon, but it's pretty pricey. They may be
called proximity testers. Can one be made easily?

audio amplifier with capacitive probes,
when the string powered there will be an increased
electic field level in the vacitinity of an open-circuit failed bulb.
and reduced field near the working bulbs.

How is that going to work if one string is working, and the other is
open?


--
You can't have a sense of humor, if you have no sense.