I've got an LM358 comparator turning on an LED. What I'd like to add is a way to dim the LED by a fixed amound when a 12v signal is sensed.
It's in a tach circuit in a car, and when the headlights are turned on the dash lights get fed power, so when that occurs it's probably dark enough where the LED should be less bright.
I've got something modeled in ltspice with a resistor and npn on parallel with the led to draw off some of the current. Does that seem sensible or is there maybe a better way? Thanks!
Here's an example of a similar 2-stage shift light in action: