Author Topic: Does this connection make any sense?  (Read 6500 times)

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Offline chupocroTopic starter

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Does this connection make any sense?
« on: April 04, 2024, 08:24:39 pm »
I am looking at the connection examples of some toggle switch from AE which has two indicator LEDs and can't see any sense in connecting the NO contact to the cathode of the green LED as in the connection diagram in the picture I marked with the red arrow.

Can anyone spot any reason why would one want to make such a connection which connects battery plus with the green LED's cathode?

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Offline AVGresponding

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Re: Does this connection make any sense?
« Reply #1 on: April 05, 2024, 05:38:47 am »
Who says it's connected to the cathode? It's more likely it's connected to the anode, and the cathode is common with that of the red LED, and that the diagram merely shows the connections for OFF=GREEN ie the device being controlled by the switch is "safe".

Or it could just be wrong, it does happen.
« Last Edit: April 05, 2024, 05:40:43 am by AVGresponding »
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Offline tooki

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Re: Does this connection make any sense?
« Reply #2 on: April 05, 2024, 11:38:22 am »
Who says it's connected to the cathode? It's more likely it's connected to the anode, and the cathode is common with that of the red LED, and that the diagram merely shows the connections for OFF=GREEN ie the device being controlled by the switch is "safe".
Ummm… the datasheet shown? On the bicolor LED model, the drawing clearly shows the “LED:+” pin, then “LED:G” and “LED:R” pins instead of the “LED:-” pin shown on the single-LED model. Since LED+ is the anode, and there’s only one, it has to be the common, meaning the cathodes are separate.
 

Offline tooki

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Re: Does this connection make any sense?
« Reply #3 on: April 05, 2024, 11:49:18 am »
Can anyone spot any reason why would one want to make such a connection which connects battery plus with the green LED's cathode?
It doesn’t make any sense at all. There’s no way for current to flow.
 
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Offline AVGresponding

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Re: Does this connection make any sense?
« Reply #4 on: April 05, 2024, 12:58:01 pm »
Who says it's connected to the cathode? It's more likely it's connected to the anode, and the cathode is common with that of the red LED, and that the diagram merely shows the connections for OFF=GREEN ie the device being controlled by the switch is "safe".
Ummm… the datasheet shown? On the bicolor LED model, the drawing clearly shows the “LED:+” pin, then “LED:G” and “LED:R” pins instead of the “LED:-” pin shown on the single-LED model. Since LED+ is the anode, and there’s only one, it has to be the common, meaning the cathodes are separate.

Yeah, I agree, it's implied. Note to self: no posting before fully waking up in the morning!

Depending on the PIV of those LEDs, it might well light the red one with enough voltage...

In fact, at 220VAC, it'll be lighting them both. For a short time...
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Offline chupocroTopic starter

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Re: Does this connection make any sense?
« Reply #5 on: April 06, 2024, 01:52:20 am »
Quote from: tooki on Yesterday at 01:49:18 pm
It doesn’t make any sense at all. There’s no way for current to flow.

There are different images with the same mistake - seems as sellers are replicating the same schemetics. Here is another one with added legend describing how it was supposed to work.

There are listings where LEDs would work as expected but the load is connected in series with the LEDs. I can't find those at the moment but I'll post the link if I find them again.
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