SPST Non illumination of LED - Driving me mad

[Phil&Monty]

Hello All,
As you can see I've only very recently come across this site. Its been such a frustrating day. It's such a simple thing but I'm not from this electronic background but a photographic one.

I have an LED SPST switch being used in a 7V DC system. On one side of the box is a 7V SLA battery and on the other side is a modified strobe light. Everything is performing really well but then I left the system on and ran the battery down. Solution put an illuminated switch in, this is when my frustration started.

The switch works as it should turning off the circuit so no problems there. Having paid for the illumination I would really like it to happen. Spent the whole afternoon trying to solve it, countless youtube videos and articles.

Some of the things that have been tried
Different switches - once this one works the box will have 5 switches
Connecting the switch to the battery to see if it illuminates (spade 1 & spade 3)
Swapping the -ve and +ve pins

The switch has three prongs and this is how I have it wired
Spade 1 silver +ve coming in from battery
Spade 2 silver +ve going out to strobe unit
Spade 3 gold -ve coming in from battery and continuing out for the strobe.

I know its pretty basic and I should be able to solve it but it seems its beyond me.
Thanks in advance
Phil

 

[davenn]

Welcome to EP

The switch works as it should turning off the circuit so no problems there. Having paid for the illumination I would really like it to happen. Spent the whole afternoon trying to solve it, countless youtube videos and articles.

photos/circuit for us to see would be really helpful
else we really cannot visualise what you are doing

 

[Martaine2005]

Sounds to me like the LED switch is probably 12V or 24V auto switch. Or 110V - 220V.
Maybe your 7V battery is not able to illuminate the LED.
Have you got a link to the switch?

I just re-read your post. The switch LED will need a positive and negative to illuminate.
Your strobe should be wired with the switch in series on the positive leg and the negative return to GND or battery negative.
But please give a link to the switch.

Martin

 

[Phil&Monty]

Welcome to EP




photos/circuit for us to see would be really helpful
else we really cannot visualise what you are doing

Please see the below photos of the box and switch. they will not upload

 

[Phil&Monty]

Works on the laptop. Please find a photo of the switch and the switch in position with the wiring. Any thoughts are most appreciated.

 

[Harald Kapp]

Please add type / model number or link to a datasheet of the switch?

 

[Phil&Monty]

Sounds to me like the LED switch is probably 12V or 24V auto switch. Or 110V - 220V.
Maybe your 7V battery is not able to illuminate the LED.
Have you got a link to the switch?

I just re-read your post. The switch LED will need a positive and negative to illuminate.
Your strobe should be wired with the switch in series on the positive leg and the negative return to GND or battery negative.
But please give a link to the switch.

Martin

Hi Martin,
Here is a link to the switch
https://www.jaycar.com.au/spst-round-red-illuminated-actuator-rocker-switch/p/SK0962
Regards
Phil

 

[Harald Kapp]

This is obviously a switch for AC 250 V with a Neon bulb inside. No chance to have this light up from a 7 V battery.

The switches I find for battery operation usually are for DC 12 V. A 7 V battery may light this kind of switch dimly - or not at all. You'd have to test these.

Alternatively, add your homebrew indicator light made from an LED and a suitable series resistor next to the switch. It is really simple, see here.

 

[Phil&Monty]

This is obviously a switch for AC 250 V with a Neon bulb inside. No chance to have this light up from a 7 V battery.

The Jaycar tech Guys said it would work and this switch is used in a lot of 12V dc auto applications. Now I'm confused. Appreciate everyones help.
Regards
Phil

 

[Harald Kapp]

The switch will work, but not the indicator. Unless your link points to the incorrect website. On the linked page it clearly states:

- 6A @ 250VAC
- Black body with red neon actuator

(emphasis by me)

 

[Martaine2005]

As suspected, probably the wrong voltage/type of switch for your project.
It could still be an innocent mistake by Jaycar employee. Wrong item put in wrong parts bin.

Out of curiosity, what is the 7V SLA battery project ?

Martin

 

[Bluejets]

Call me crazy but why would one need an LED illuminated switch when the switch turns on a light, a strobe light at that.

 

[Phil&Monty]

I really thought it was like a maximum voltage that the switch could handle. Anyway willl try and get a 12V illuminated switch.

A bit more about the project.
I have modified several speedlight/strobes from AA batteries to work from SLA batteries. This results in a longer shooting time for the high speed setup. The box with the switches is to control power supply to the individual flashes. The reason for the illumination is the studio is dark during the shooting process.

Once again appreciate the help
Regards
Phil

 

[Harald Kapp]

I really thought it was like a maximum voltage that the switch could handle.

It is - and a neon lamp that will light up at 250 V will not light up at 7 V.

Anyway will try and get a 12V illuminated switch.

Do that but don't be disappointed if the illumination doesn't work from the 7 V battery voltage.

In any case it is no big deal to add an LED indicator designed for 7 V at the output of the switch:

Assuming a red LED and a LED current of ~ 20 mA, this circuit may shine a bit too bright in your dark photo studio. To dim the LED, use a 330 Ω or 470 Ω resistor instead. A wattage of 250 mW for the resistor is more than enough. Note that an LED is a polarized element. You need to observe the correct connection of anode ("+") and cathode ("-").

 

[Phil&Monty]

It is - and a neon lamp that will light up at 250 V will not light up at 7 V.

Do that but don't be disappointed if the illumination doesn't work from the 7 V battery voltage.

In any case it is no big deal to add an LED indicator designed for 7 V at the output of the switch:
View attachment 49113
Assuming a red LED and a LED current of ~ 20 mA, this circuit may shine a bit too bright in your dark photo studio. To dim the LED, use a 330 Ω or 470 Ω resistor instead. a wattage of 250 mW for the resistor is more than enough. Note that an LED is a polarized element. You need to observe the correct connection of anode ("+") and cathode ("-").

Superb Harald, will get this happening on the weekend. Much appreciated

 

[Phil&Monty]

Big thanks to everyone who helped out. The box has been finished and tested in the studio.