I have a question about driving LED in different, inverted way: the LED should light on when the signal/state is LOW (0V) and the same LED should be turned off when the signal is HIGH (5V).
I have attached a schematic which this solution with two npn transistors to do it simply without specific IC's.
But I wonder what about efficiency. If we think about using ONLY transistors (bipolar or MOSFET, doesn't matters), is it the best way (I mean this circuit configuration strictly) to drive the LED with a reasonable low current drawn by the circuit? I ask because driving LED circuit in inverted way requires to be powered the whole time. In other words - I am asking about the most current-efficient LED control path when using only transistors, when we want the LED to shine (the diode current should be sufficient to be able to shine clearly) when the IN pin is low. Or maybe is it possible to do it by other type of transistor than npn?
driving LED in different, inverted way... it is
controlling LED in inverted way\$\endgroup\$