Where to find a few 120V indicator indicator lights?

[Ted Swirsky]

I can't believe it's so hard to find simple parts any more. Radio Shack
seems to have become worthless in the past few years.

I installed a 120V neon indicator (pilot) lamp in some of my wall switches
to tell me when an outside or otherwise unseen light is on. Seems like
these little neon lights get dimmer over time until they are worthless.

I've heard of 120V LED pilot lights. Are they much better than the neon
ones?

I'm looking for a known mail order supplier who will sell me only two or
three at a reasonable price and not kill me on shipping. I'm surprised I
didn't see them on the Hosfelt Electronics site. I've found them on some
other sites but the prices seemed kind of high to me. I thought someone
here would know of some good suppliers.

I'd just buy a switch with a pilot light, but some of the places I
installed them are double wall switches (two in a group) and are of the
fancy rectangle switch kind instead of the older toggle switch. I just
drilled a hole in the switch place between the two switches for the lamp.

Any help or comments or alternate ideas would be appreciated.

Thanks!

Ted

 

[ALBERT C. GOOD JR.]

Hi Ted
May I suggest several things.

1. those square switches can probably b had with built in indicators that
are part of the rocker.

2. Both neon and LEDs require a ballast resister which with out they will
meet their demise before the intended time. Also since a LED is as its name
would imply, a diode and therefore conducts only on one half of a cycle
unless you wish to use a bridge rectifier with it.

3. Also I would advise that you should be certain that the combined devices
meet applicable safety regulations.

3. A good place to find all sorts of electronic parts would be Allied
Electronics which was or is part of Radio Shack. If you look around on
their web site you should find a page with menu that allows you to order
their phone book size catalog, which I received for free about 6 months ago.

Cheers.. Al

 

[petrus bitbyter]

I can't believe it's so hard to find simple parts any more. Radio Shack
seems to have become worthless in the past few years.

I installed a 120V neon indicator (pilot) lamp in some of my wall switches
to tell me when an outside or otherwise unseen light is on. Seems like
these little neon lights get dimmer over time until they are worthless.

I've heard of 120V LED pilot lights. Are they much better than the neon
ones?

I'm looking for a known mail order supplier who will sell me only two or
three at a reasonable price and not kill me on shipping. I'm surprised I
didn't see them on the Hosfelt Electronics site. I've found them on some
other sites but the prices seemed kind of high to me. I thought someone
here would know of some good suppliers.

I'd just buy a switch with a pilot light, but some of the places I
installed them are double wall switches (two in a group) and are of the
fancy rectangle switch kind instead of the older toggle switch. I just
drilled a hole in the switch place between the two switches for the lamp.

Any help or comments or alternate ideas would be appreciated.

Thanks!

Ted

Ted,

IMHO the simple neon bulbs are still the easiest indicators. They will last
long, most of the times longer then the equipment they are build in. That's
where I get most of them from. Neon bulbs are made for various currents.
They will give more light and live shorter when you feed them more then the
nominal current. Less current gives less light but a longer lasting
indicator. Neon bulbs are for sale by Farnell for instance. But, of course,
you'll have to pay much more for handling and shipping then the price of the
bulbs.

If you can get the right LEDs cheaper they are a good alternative. But LEDs
require verry low voltage and relative high currents. So a "standard" 20mA
LED will consume almost 2,5W to be dissipated in the serial resistor. I ever
made a circuit to use such a LED even at 230V but it takes quite some space
(and money). So to keep things simple, you'll have to use high efficiency
LEDs that require 2mA or even less. To make it really efficient you'll have
to add a bridge rectifier but four small general purpose diodes will do.
Sometimes someone advises to use one antiparallel diode but then you throw
away half of the light you can have for the same money.

petrus bitbyter

 

[John]

Both neons and LEDs have the same problem - series ballast resistors. These
high value resistors with high voltage drop always drift high over time,
reducing the current and leaving the light dim. The solution? If you can
hack the fitting apart, replace the resistor. Pretty simple job really. I've
never found the neon or LED to have actually dropped in efficiency. It's
always the resistor.

 

[default]

I can't believe it's so hard to find simple parts any more. Radio Shack
seems to have become worthless in the past few years.

I installed a 120V neon indicator (pilot) lamp in some of my wall switches
to tell me when an outside or otherwise unseen light is on. Seems like
these little neon lights get dimmer over time until they are worthless.

I've heard of 120V LED pilot lights. Are they much better than the neon
ones?

I'm looking for a known mail order supplier who will sell me only two or
three at a reasonable price and not kill me on shipping. I'm surprised I
didn't see them on the Hosfelt Electronics site. I've found them on some
other sites but the prices seemed kind of high to me. I thought someone
here would know of some good suppliers.

I'd just buy a switch with a pilot light, but some of the places I
installed them are double wall switches (two in a group) and are of the
fancy rectangle switch kind instead of the older toggle switch. I just
drilled a hole in the switch place between the two switches for the lamp.

Any help or comments or alternate ideas would be appreciated.

Thanks!

Neon lights are hard to beat for simplicity and light output.

LEDs are practical in that application. I have a LED night light it
stays on 24/7 and I replace the three leds about every four years
because they get dim

Don't use a resistor to drop the voltage if you use a LED - use a
capacitor. costs more, but dramatically lowers the heat and power
consumed.

I use a bridge rectifier for the three leds and a .47 UF 200 VAC cap
to limit the current into the rectifier. (at 60 cycles and 120 volts
- 240 volts would be half that value) Use a 100 ohm 1/4 W resistor in
series with the cap. Ideally it "should" be a flameproof resistor but
the standard carbon film ones open without burning if the cap shorts.
(which I managed to do while assembling my light - didn't even singe
the paint on the resistor - tiny flash of light - and shorted all
three leds)

The resistor limits the inrush current to the led and works as a fuse.
You could ditch the rectifier and use two leds in a back to back
configuration to work on each half cycle of the sine wave. One LED
and a diode in series with the LED or across the LED so it is forward
biased when the LED is reverse biased.

If you use half wave power you can double the current for the same
light output. Calculate the capacitive reactance to determine the cap
size needed for the voltage and frequency of your mains and current
you intend to run.

 

[petrus bitbyter]

Neon lights are hard to beat for simplicity and light output.

LEDs are practical in that application. I have a LED night light it
stays on 24/7 and I replace the three leds about every four years
because they get dim

Don't use a resistor to drop the voltage if you use a LED - use a
capacitor. costs more, but dramatically lowers the heat and power
consumed.

I use a bridge rectifier for the three leds and a .47 UF 200 VAC cap
to limit the current into the rectifier. (at 60 cycles and 120 volts
- 240 volts would be half that value) Use a 100 ohm 1/4 W resistor in
series with the cap. Ideally it "should" be a flameproof resistor but
the standard carbon film ones open without burning if the cap shorts.
(which I managed to do while assembling my light - didn't even singe
the paint on the resistor - tiny flash of light - and shorted all
three leds)

The resistor limits the inrush current to the led and works as a fuse.
You could ditch the rectifier and use two leds in a back to back
configuration to work on each half cycle of the sine wave. One LED
and a diode in series with the LED or across the LED so it is forward
biased when the LED is reverse biased.

If you use half wave power you can double the current for the same
light output. Calculate the capacitive reactance to determine the cap
size needed for the voltage and frequency of your mains and current
you intend to run.

A series capacitor is a good idea if price and dimensions will give no
problem. It's even better if heath is (a problem). You will save energy as
you have less dissipation. I only consider the 100 Ohm resistor pretty low
to suppress the inrush current. It may do for a 24/7 nightlight but in
equipment that has to be turned off and on several times a day, the LEDs may
degrade or blow pretty fast. After all the worst case peak current will be
over 1.5A. To stay on the safe side, this peak current should not exceed the
LEDs peak current. The latter depends on the LED you use, so you'll need its
datasheet.

petrus bitbyter.