Neon indicator to 240v wall light switch

Thread Starter

ekremgusani

Joined Mar 20, 2011
157
How to add Neon (as the led is prohibited by admin) indicator to existing 240v wall light switch?
I want the neon to lite when the switch is at OFF position and led to turn off when light switch is at ON position.
I have already installed those neon indicator switches that i bought from Amazon but I would like to know to make one.
Will appreciate schematic of the circuit.
Thanks!
 
Last edited:

MaxHeadRoom

Joined Jul 18, 2013
20,472
@Dodgydave came up with one answer is to wire the neon across the switch, it will light when the switch is off, you can get small panel mount types used in appliances such as freezers etc.
Max.
 

Reloadron

Joined Jan 15, 2015
5,370
I would take the neon bulb suggestions and keep in mind depending on the switched load you may want a resistor in series with the neon bulb. You can buy wall switches which do exactly what you are looking for. Any home improvement store should have them. They are nice when looking for the light switch in a dark room.

A Google of "illuminated wall switch wiring" should yield several circuits but as mentioned you basically place your neon bulb across the switch terminals.

Ron
 

MrChips

Joined Oct 2, 2009
20,919
Let's be reasonable here. The no "LED to mains" prohibition is to disallow discussion of powering LED light strips etc. directly from AC mains.

Neon power line indicators are commonly used to indicate power ON on instrument panels.
Remember that you will need a resistor (about 330kΩ) in series with the neon lamp to limit the current through the lamp (assuming that there is no built-in resistor).

You can place the neon indicator across the ON/OFF switch to indicate power OFF.
Or you can place the neon indicator after the ON/OFF switch to indicate power ON.
 

Kjeldgaard

Joined Apr 7, 2016
398
Be aware that with a Neon or other low current indicator lamp installed over a switch, a "fault current" will occur in the main lamp.

With a filament lamp this will be no problem, but with a LED lamp or CFL (Compact Florescent Lamp) maybe a small blink with second intervals can be seen.
 

Thread Starter

ekremgusani

Joined Mar 20, 2011
157
I would take the neon bulb suggestions and keep in mind depending on the switched load you may want a resistor in series with the neon bulb. You can buy wall switches which do exactly what you are looking for. Any home improvement store should have them. They are nice when looking for the light switch in a dark room.

A Google of "illuminated wall switch wiring" should yield several circuits but as mentioned you basically place your neon bulb across the switch terminals.

Ron
I already have few of them as I mentioned above but i want to know how to make one..
 

btebo

Joined Jul 7, 2017
95
How would you use a neon light to turn on if a fuse is blown (I've seen fuse holders like this).... If the connections are across the fuse (a la the switch circuit), wouldn't some current still flow to the load through the neon light circuit?
 

Thread Starter

ekremgusani

Joined Mar 20, 2011
157
Let's be reasonable here. The no "LED to mains" prohibition is to disallow discussion of powering LED light strips etc. directly from AC mains.

Neon power line indicators are commonly used to indicate power ON on instrument panels.
Remember that you will need a resistor (about 330kΩ) in series with the neon lamp to limit the current through the lamp (assuming that there is no built-in resistor).

You can place the neon indicator across the ON/OFF switch to indicate power OFF.
Or you can place the neon indicator after the ON/OFF switch to indicate power ON.
Thanks.
 

MaxHeadRoom

Joined Jul 18, 2013
20,472
How would you use a neon light to turn on if a fuse is blown (I've seen fuse holders like this).... If the connections are across the fuse (a la the switch circuit), wouldn't some current still flow to the load through the neon light circuit?
Yes I use these type of fuse holders, but the current is not dangerous to personnel, just about the same as using a Electricians neon ind. screwdriver to detect voltage, the current, which is exceedingly small passes through one's body to ground without one sensing it.
Max.
 
Last edited:

btebo

Joined Jul 7, 2017
95
Yes I use these type of fuse holders, but the current is not dangerous to personnel, just about the same as using a Electricians neon ind. screwdriver to detect voltage, the current, which is exceedingly small passes through one's body to ground without one sensing it.
Max.
Thanks, Max. Being a NOOB - I assume the low current is due to the large value resistor that is in series with the neon lamp? I believe earlier someone suggested a 330kohm resistor - so the total current through the circuit (at 120 vac) is approx 0.36mA (120V/330kOhm = .00036A)?
 
Last edited:

MaxHeadRoom

Joined Jul 18, 2013
20,472
There is also the resistance of the Neon gas/arc, typical R values I have seen in use, are 150k and up, depending on the voltage source.
Max.
.
 

MrChips

Joined Oct 2, 2009
20,919
You did say your AC mains voltage is 240V.

Peak voltage is 240 x 1.4 = 336V
Subtract the neon voltage = 90V
Voltage across resistor = 336 - 90 = 246V
Divide by series resistor = 330k
gives current I = V / R = 246 / 330k = 0.75 mA
 
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