i got a NPN input NPN output board from Eletechsup with this diagram. I connect 5V to COM, 0V to GND, 5V to VCC, and Y1 output is 3.5V without X1 trigger. when X1 is pull to Ground GND 0V, Y1 is triggered to output 0V too. when i connect 5V to COM, 12V to VCC, Y1 output is 7.5V without X1 trigger. why? When COM = 5V, VCC=5V, Y1 is 3.8V, X1 = 0V, Y1 is 4V, X1 = 3.5V. trigger voltage seems to be 3.8V-3.9V. why?Answer :pls follow this picture :
