Parallel lighting main.

MRail

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Dtsteam said:
My question is more around the DCC signal, which I understand is an AC signal of roughly 8Khz. Can I just connect an led and resistor or do I need something else ?

Sorry, I'll have to pass on that one, being a steam and battery "SM32" operation.
 

stockers

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DCC is almost AC, so it will need to have a rectifier in the circuit.
 

ntpntpntp

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A single LED in an alternating current circuit will only light for half the cycle and needs to be protected by a diode wired inverse-parallel.

You could use a pair of LEDs wired inverse-parallel but each one is still only be lit for half the cycle. For your usual 50hz AC sine wave from a train set controller, that can result in a noticeable flicker. DCC is not a constant frequency alternating current, but averages out at a somewhat higher frequency so the flicker is much less noticeable. If you want proper smoothed DC then you need a bridge rectifier and smoothing capacitor.

At least, that's my understanding.
 

Dtsteam

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Thats what I was after. Is this what you mean by inverse - parallel, and can I then put the pairs in series with one resistor ? (excuse the really naff sketch) I'm assuming the resistance value stays the same as a single series array as only one of each pair is lit at a time.

2400789ee4f04e2f972fc1fd4bae14b3.jpg


Time to hit Maplins and kill some Leds methinks !
 

MRail

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ntpntpntp said:
A single LED in an alternating current circuit will only light for half the cycle and needs to be protected by a diode wired inverse-parallel. You could use a pair of LEDs wired inverse-parallel but each one is still only be lit for half the cycle.

That would be correct - the multpile garden lights appear to be dual LED's.
To the eye they are lit constantly, but in photos (attached) some are off, although the supply is constant and common to all.
da46a8b0d228460e90dafab67febe434.jpg
 

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leds, on a dedeciated 12 volt(car batteary charger) surplly, ring main...
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