ECE 3300 Name:_________________

Exam #2 (Fall 2017) (75 minutes. 20 points per problem)

Prof. Mohamad Hassoun

1. Fill in all 12 entries in the matrix representation of the nodal voltage

equations for the following circuit (Hint: You may do it by inspection).

2. a. (15 points) Determine 𝑅𝐿 so that it dissipates maximum power. Assume 𝛼 ≥ 0.

b. (5 points) What is 𝑅𝐿 if 𝛼 = 0? Note: Part b can be solved independent of

Part a.

3. Consider the following circuit.

a. (15 points) Derive an expression for 𝑣𝑜 as a function of the resistances and 𝑣𝑖𝑛.

b. (5 points) Determine lim𝑅5→∞

𝑣𝑜. Note: Part b can be solved independent of Part a.

4. Determine 𝑅1 in the following circuit such that the LED is switched ON

(assume that the LED has 𝑣 = +2V and 𝐼 = 20mA).

a. (15 points) Which op-amp(s) specified in the provided table are

appropriate to be used in this circuit?

b. (5 points) Determine the power supplied by the op-amp to the rest of the

circuit.

5. Consider the following amplifier circuit and refer to 𝑣𝑜

𝑣𝑖𝑛= −𝐾 as the

amplifier gain. Assume the VCVS model shown for the op-amp, where

𝐴 is finite and 𝑣𝑑 is non-zero.

a. (15 points) Determine the gain 𝐾 as a function of 𝑅1, 𝑅2 and 𝐴.

b. lim𝐴→∞

𝐾 =? (Note: The question can be answered independent of Part a.)