I have a simple question about calculating resistor.
I have lots of leds driven by negative, wired with one resistor for each one and 2 leds wired together. I can't modify this as it's enclosed in a box. This is the schematic on the left.
I need to lower the current in the leds, to lower the light amount.
My only option is to add a resistor, like on the right schematic. One resistor for 2 leds+resistors.
How can I calculate the new current flowing through the leds or equivalent resistor? Everything I've found on internet is parallel or serial network, but never parallel + serial.