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Minimum Resistor Value for Seeklights used with timer modules

I want to use a Seeklight that has an LED lamp fitted and needs a resistive load to operate properly.

I want to use 2 x 8 pieces of Seeklights for a hallway / staircase timer delay lighting circuits in two apartment blocks.

No filament lamps are included in the energising circuits for the existing Hager EMN001 timer modules.

Question: What is the minimum series resistor value required for this arrangement to complete the circuit to Neutral? I would like to avoid using a filament lamp for that purpose only if possible.

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  • Firstly the resistor will need to be in parallel with the LED lights, not in series,

    Ideally you want the mains accross the 'light seeker' when the switch is open circuit and the main LED light is off, and then the seeker is shorted by the switch and the LEDs get full mains when the switch is on.

    The problem is that the LED fitting switches to being an open circuit and draws almost no current at all when off, so there is a bun fight between the pattress illumination trying to trickle current  round the switch and the LED fitting not really on or off, and the results can be odd flicker effects and a rather uncertain voltage division effect.

    Something that looks like a steady load  in shunt with the LEDS means the load  voltage falls to much nearer zero so most of the 230V is across the opened switch contacts , and so the pattress light works as intended.

    Of course if you do not mind it being on all the time, instead of wiring across the switch you could run it between steady live and neutral.

    Do you have a part no or makers datasheet ?

    Are these the Crabtree ones ? if so the pattress illumination current is similar to a neon lamp of 2-3  mA, and 50k-100k ohms is about right, in a size suitable rated for mains voltage of course.

    Or a capacitor of about 0.1uF (== 100nF) or standard snubber (typically that  is 0.1uF series 100ohms inside ) fitted in parallel with the LED fittings will have the same effect and less waste heat dissipation.

    If you have no data, then as a test just  run the light seeker across the mains via a series meter on the AC milliamp range, and make a note of the current it takes when lit. Mind your fingers of course.

    Divide 50V (to ensure the LED stays off)  by that current and anything between that and half that value should do.

    remember that volts and milliamps give answers in k ohms.

    If this makes no sense please come back for a less rushed explanation

    Mike.

  • Thanks Mike.

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