The blue trace is the input voltage. Green trace is the reference voltage. Orange trace is the output. This is an op amp comparator. It compares the voltage at the + input with the voltage applied to the - input. When the voltage at the - input > the voltage at the + input the output will go high and vise versa. The reference voltage can be set to whatever voltage you want. The output will go as high as the applied vcc of the oppamp. And will go as low as the negative supply(which can be ground).
