ECE2006 UMD Spring, 2011
Name: _____________________
FINAL EXAM: 100 Points (25% of Grade) – Show Work for Partial Credit
1.
(20 Points) In this DC steady-state circuit use any method to find: a.
Io b.
The power dissipated in each 10 ohm resistor
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ECE2006 UMD Spring, 2011
2.
(20 Points) In this RC transient circuit, the switch has been closed for negative time and opens at time zero. Find the following: a.
Vc(0) b.
Vc(∞) c.
Tau, the RC time constant of the circuit d.
Write the equation for Vc(t), valid for all positive time.
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ECE2006 UMD
3.
(20 Points) Complete the table for this second order transient circuit:
Quantity
Alpha, α
Omega, ω
S1, S2
Vc(0)
Vc(∞) dVc(0)/dt
I
L
(0)
I
L
(∞) dI
L
(0)/dt
I
L
(t) =
Value
Spring, 2011
Amps
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ECE2006 UMD Spring, 2011
4.
(20 Points) Use Phasors (either RMS or Peak Value, your choice) to calculate the following for this AC, steady-state circuit: a.
Z1, Z2, and Z3 as complex impedances in Ohms b.
The parallel combination Z2//Z3 c.
Zs, the total impedance as seen by the voltage source d.
Va, the node voltage at a , by any method e.
P5, the average power dissipated in the 5 Ohm resistor
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ECE2006 UMD Spring, 2011
5.
(20 Points) For the electric current, i(t) , graphed below, make any assumptions necessary to find the following: a.
Write the set of equations that describes i(t) algebraically b.
Assuming an initial charge, q(0) = -1mC , apply calculus to determine a set of equations for q(t) , the electric charge associated with this current c.
Sketch q(t) on the graph provided
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