ECE 220 Practice Exams

PART I

Current in ideal coil rises linearly when a DC voltage source is applied.

Ouput current of comparator is -1.33mA

After switch is closed, current on secondary coil flows momentarily in
direction shown (consistent with + polarity at top of resistor)

Cap stores 0 energy, coil is a short and passes 1A with mag field energy
of 0.5J

Two ckts have gain of +1: Buffer ckt, plus two-inv-amps-in-cascade with
total gain of -1 x -1 = 1

Analog voltmeter is designed to read 20V full-scale

When independent sources are doubled, all node voltages and all branch
currents double in size

PART II

op-amp with 3 input sources has vo = 2.55V

current-to-voltage op-amp has gain of -120,000

voltage across current source in series with coil and resistor = 3.2 mV

voltage induced in secondary coil due to sinusoid current in primary =
-11.31 kV

Instrumentation/Diff amp clips at -10V and produces load resistor current
of -250 microamps

Cap with sawtooth current stores 36.1mJ after 30ms

Output current in inverting op-amp and 6V input source is 2.364 mA