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Constant voltage and current

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A LED with a high voltage capable current source can work. A moderate current of 5 mA is already generating 1.1W power dissipation however.

i meant - what sort of source are you using which has a range of 12v to 220v ?

Ultimately you may want to add 230 VAC to the specification.

I remember, that I previously designed industrial controllers with an e.g. 15 VDC to 230 VAC voltage range for binary signals. In some cases there might a similar specification for indicator lamps. The most serious argument against it is that you sometimes observe residual voltage levels of several ten volts in open 230 VAC circuits. Thus a wide range control input might be trigerred and an indicator lamp flicker in this situation.

I already mentioned a current source as straight forward solution, it would need a high voltage transistor as active element.

I also have an old Steinel VoltCheck 1A, a simple 4.5 to 380V AC/DC voltage indicator, using mainly a NTC to achieve an (almost) constant current.
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