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ECE 1250 Midterm I – Exam Topics: Op Amps
You may also need to use the following concepts to solve the op amp problems: voltage /current dividers,
KVL/KCL, Node-Voltage, resistors in series/parallel, Ohm’s Law.
1)
Identify common Op Amp Circuits. Be able to identify common op amp circuits. These are the op
amp used as a switch (no feedback), inverting and non-inverting amplifiers, inverting and non-inverting
summers, voltage follower, difference amplifier. Example: See Op Amp Cookbook on Recognizing Inverting
& Non-Inverting Amplifiers (see links online). More Examples: See all of the Op Amp HW & Similar
Problems, and be able to tell what kind of circuit each is dealing with.
2)
Design common Op Amp Circuits. Be able to design (specify the resistors for) the common op amp
circuits above. Understand voltage rails and the linear region of the circuit. For example: Design a circuit
where Vo = 3Vin
Examples: See Op Amp Cookbook, and Problems 4.9, 4.15, 4.26
3)
Compute the output voltage or current for a general op amp circuit. Use the ideal op amp
assumptions (In = Ip = 0, Vp=Vn, Vo = A(Vp-Vn) where A is very large) to simplify the circuit. Then solve the
circuit using voltage /current dividers, KVL/KCL, Node-Voltage, resistors in series/parallel, Ohm’s Law, etc. I
will suggest a method for solving the problem, but you may use any method that works.
Example: Use Node-Voltage to :
4)
Design an electrical system using Op Amps. Be able to design a block diagram of an electrical
system, be able to design the individual blocks of that system (as in 3 above), and be able to determine if any of
the op amp(s) in your system will saturate for a given set of input voltages. Be prepared to EXPLAIN your
system (tell how it works, what all of the interim voltages and currents are between the blocks of your block
diagram).
Example2: Design a system where Vo = 3 ( V1 + V2) – 4 V3
Example3: Design a system where Vo = 15V IF V1>V2 and V3>5V.