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Dave Platt[_2_] Dave Platt[_2_] is offline
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Default I'm looking for the little buttons that you install

In article ,
bilou wrote:
On 13/04/2021 20:55, John Robertson wrote:



Here is a story from 1981 about these buttons - Bulb Miser and Light-Saver:

https://www.washingtonpost.com/archi...-0072dc20f578/


Perhaps that will help your quest! At least you now have the names...

John :-#)#


Thanks for the link
In France I have never heard of such devices.
May be because at that time most lamps sockets were bayonet type.
I tried the diode in a switch but 220v smaller filaments and 50Hz
lower frequency produced an annoying blinking.
I saw the diode used in drills and heating devices.


As I understand it - the Bulb Miser is a thermistor (positive
temperature coefficient). It reduces the current surge into a "cold"
incandescent bulb filament, reducing the chance of a burn-out at that
time, and thus extends the life of the bulb. It does reduce the light
output and raises the operating temperature of the socket.

The Light-Saver is one of a number of diode-type "bulb savers". As I
recall, these sorts of devices do reduce the filament temperature and
thus extend the bulb's life, but they have several disadvantages:

- Greatly reduced light output (by about half)

- Reduced efficiency. Since the filament is operating at a lower
temperature, a lower percentage of its output is visible than
during normal operation, and there's (relatively) more non-
visible infrared. You get less visible light per watt.

- Radio frequency interference. The rectification effect creates
sharp edges in the current waveform, and this creates RF energy.
AM and other radio reception can suffer (buzzing, reduced
sensitivity, etc.).

- Asymmetric load on the mains. If you have a bunch of these in
use at the same time, and if the diodes all line up the same way,
the circuit will draw more current on one half of the AC waveform
than on the other. This can lead to humming and buzzing in
transformers.

Neither of these sorts of "bulb savers" are good for use with either
fluorescent or LED bulbs.

An alternative to these (if you really do insist on an incandescent
bulb) is to buy a bulb made for limited-service locations (e.g. outdoor
fixtures) which has a "130-volt" filament rating. When run on the
lower voltages that are normal, the filament runs "cool" and lasts
a lot longer than a standard bulb. You still have to accept the reduced
efficiency (lower light output per watt).