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EIE 211 Homework 1
Due next class
1. The circuit in figure below utilizes an ideal op amp.
a) Find I1, I2, I3 and Vx
b) If Vo is not to be lower than -13V, find the maximum allowed value for RL
2. For an amplifier having a slew rate of 60 V/s, what is the highest frequency at which a 20-V
peak-to-peak sine wave can be produced at the output?
3. An op amp is connected in a closed loop with gain of +100 utilizing a feedback resistor of 1MΩ.
a) If the input bias current is 100 nA, what output voltage results with the input grounded?
b) If the input offset voltage is +/- 1mV and the input bias current as in (a), what is the largest
possible output that can be observed with the input grounded?
c) If bias-current compensation is used, what is the value of the required resistor? If the offset
current is no more than one-tenth the bias current, what is the resulting output offset
voltage (due to offset current alone)?
d) With bias-current compensation as in (c) in place what is the largest dc voltage at the ouput
due to the combined effect of offset voltage and offset current?
4. Figure on the next page shows a ckt that performs the high-pass STC function. Such a ckt is
known as a first-order high-pass active filter. Derive the transfer function and show that the
high-frequency gain is (-R2/R1) and the 3-dB frequency ωo = 1/CR1. Design the ckt to obtain a
high-frequency gain of 40 dB, and a 3-dB frequency of 1000 Hz. At what frequency does the
magnitude of the transfer function reduce to unity?
5. From the figure below, find the expression of iO.