Subtractor Circuit

[uranyum444]

Hello my question is i want to declare on the Pspice subtractor.But i have no ideas how to design the circuit.Does anyone know about subtractor.I found many pages in internet but i dont see real circuit design.Our teacher said to me this device has resistor capacitor and one more element.İf you have picture about circuit design can you share with me?

 

[unclejed613]

maybe you mean an op amp or diff amp used in subtract mode (differential inputs). or maybe you mean a differentiator, which outputs the differential vs time of an input (the output is proportional to the rate and direction of change of a voltage).

shown below is a differentiator with input and output (forgive the crude representation) voltages. the decay slope of the output voltage is determined by the time constant 0.67(RC).