I have a DC high voltage (>270V) high current (>40A) circuit which needs to power a standard LED along the way to a heater. The LED is to indicate whether or not the heater is activated.
I'm struggling with dropping down the power to light the LED, whilst losing as little power as possible and maintaining an acceptable level of luminosity. Unfortunately I don't believe a potential divider will work, since the voltage source is variable (due to heater requirements) from around 30V to 300V.
What I need to be able is to have a stable low voltage signal powering a standard LED which shows whether there is voltage, with constant luminosity no matter the amount of voltage. Hope this makes sense.
Ideas I have looked at so far, without much success, are potentionmeters (power will be too high) and non-contact solutions (seem to only work with AC). A logic gate might work, but I wouldn't know how to incorporate a high power gate into this circuit.