Indicator for outside lights

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A diode from each switched live to a common neon. Each diode the same way round. easy.
Clever. Although I wrote ...
The problem is that it's AC - were it DC, you would only need diodes!
...it did not occur to me that, in this case, we didn't need AC to power the indicator (provided the neon uses a resistor, and not a capacitor!)
 
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Clever. Although I wrote ...

...it did not occur to me that, in this case, we didn't need AC to power the indicator (provided the neon uses a resistor, and not a capacitor!)
You could use a big fat LED with a big fat resistor on the back of it :)
 
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Surely that would have the same effect as using double pole switches, would it not?
Using dp switches like mikeyd suggested obviously allows each of the four switches (that are all located together) to switch each light individually whilst each, (or any combination of switches) to also illuminate the indicator.

Linking all four switch wires together would obviously bring on all four lights regardless of which switch is operated. The whole point of individual operation would be lost.
 
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Historically I've used a 'series' indicator LED module and quoted it these hallowed pages before. It would have been perfect for the job in hand:
1655545168399.png

IIRC they had a volt drop of 2-2.7V. I have used loads of them.
Sadly I went to my regular wholesaler earlier this year to find they have been discontinued as too many were being returned 'blown up'.
I imagine it's just a few diodes and a limiting resistor:
1655546724105.png

So re-engineering a grid module may not be out of the question.
 
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I can think of all sorts of theoretically possible approaches, but most would be far too complicated for the task!

The problem is that it's AC - were it DC, you would only need diodes! As you sort-of imply, one of the (conceptually, but not practically) 'simplest' method would be to use four relays.

However, although the lights are all individually switched, is there a common feed to all of the switches? If so, the task becomes a lot simpler, since all you then need to do is detect/indicate whether or not any current is flowing though that one feed. At it's simplest, that could be an incandescent bulb, or maybe small transformer (the secondary of which powered the 'indicator') in-line in that feed..

Kind REgards, John
The diode-OR feature works on AC as well as DC. With a single diode in each lamp feed, there will be a 1/2wave signal available at each diode output. By coupling these outputs to a single indicator, when any diode is 'active' the OR signal is available. Because adjacent diodes are reverse biased there will be no power fed back to the non-powered lights. Been there, done it. I suggest using 1N4007 diodes.

Edit : Just seen that Winston beat me to it >
 
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You could use a big fat LED with a big fat resistor on the back of it :)
Yes, I almost mentioned that but, on reflection, didn't bother since neon gridswitch modules are (have been) 'the norm' (I don't know if there are now LED ones).

The LED does not need to be any more 'big and fat' than one needs for the desired brightness. The resistor would, however, have to be fairly substantial, since with an LED current of, say, 10 mA it would have to dissipate about 2.3W.

Kind Regards, John
 
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The diode-OR feature works on AC as well as DC. With a single diode in each lamp feed, there will be a 1/2wave signal available at each diode output.
Following winston's unusually helpful comment, I've conceded that, but it's only true in this sort of (I would say very unusual) situation in which it is acceptable for the OR-ed signal not to be 'proper AC'.

More generally, one obviously cannot OR-together AC signals with diodes and get 'proper AC' as the 'output', and I imagine that there are few situations (other than ones such as we are considering here0 in which a half-wave rectified output would be acceptable.

Kind Regards, John
 
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John. There is nothing unusual about my helpful comments. Here is another. Add a capacitor across the neon to smooth the supply.
 
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John. There is nothing unusual about my helpful comments.
That is clearly a matter of opinion
Here is another. Add a capacitor across the neon to smooth the supply.
Another (theoretically) sensible comment - although, having just tried with a (MK) neon grid module (and a IN4007) it seems fine without a capacitor.
 
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Following winston's unusually helpful comment, I've conceded that, but it's only true in this sort of (I would say very unusual) situation in which it is acceptable for the OR-ed signal not to be 'proper AC'.

More generally, one obviously cannot OR-together AC signals with diodes and get 'proper AC' as the 'output', and I imagine that there are few situations (other than ones such as we are considering here0 in which a half-wave rectified output would be acceptable.

Kind Regards, John
I fully concur with your comment but the purpose was to satisfy the writer's requirement in a simple and (not particularly unusual) cost-effective manner
 

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