Hello, I am trying to use a BC547B NPN transistor as a switch to control a 5mW red laser, but I can't get it to work.
I believe it is because I have the wrong resistor to control the current on the base.
Does anyone here know how I can calculate R1 in the sketch below? Please ignore the laser component name (QED123), it is just a side effect of picking a random LED component to symbolize my laser.
I am unfortunately stuck. Have tried random values for R1, but no luck.