Circuitos tarea 1 - itesm

TE1002. Electric Circuits I J.F. Alfaro, PhD

ITESM Spring 2011

Solution Problem Set #1
Handed Out: Thursday, 01/13/11 Due: Monday, 01//17/11 1. Reading assignment. a. Chapters 1 and 2 oftextbook [Hayt et al, Engineering Circuit Analysis (Análisis de circuitos en ingeniería)] -ProblemsHandwritten and with the statements of each problem, indicate every step and how did you find thesolution. [1] In a certain digital circuit, a logic gate switches from the “on” state to the “off” state in 25 ns. This corresponds to: 3 3 (a) 2.5x10 ps ; (b) 25 x10 ps;(c) 2.5 ps; (d) 250 ps; (e) none ofthe above

[2] A typical incandescent reading lamp runs at 60W. If it is left on constantly, how much energy (J) is consumed per day, and what is the weekly cost if energy is charged at a rate of 12.5cents per kilowatthour? (Remember that Watts=Joules/seconds) Energy:__5.18x106___[J] or 5.18 MJ , Cost: $_1.26_____

[3] In the wire shown below, electrons are moving left to right to create acurrent of 5 mA. Determine the value and sign of I1 and I2.

I1

I2 I1:_-5x10-3_[A] or -5 mA
,

I2: ___+5___[mA]

[4] For the element in the figure below the voltage, v1=12 V. Determine v2. + v1
v2 

 v2:___-12___[V]

[5] Find the current in an element when the charge entering the element is q = 12t [C] where t is the time in seconds

i=dq/dt=__12___[A]

TE1002. ElectricCircuits I J.F. Alfaro, PhD

ITESM Spring 2011

[6] Find the charge that has entered the terminal of an element from t=0 s to t=3 s when the current entering the element is as shown in the figurebelow. (Remember how the current is defined with respect to the charge and solve for different sections of time). q:___5__[C] i (A)    











t (s)

We candescribe i(t) as

 0 t0  i (t )  1 0  t  1  t t 1 
Thus we have:

q   i (t )dt   1dt   t  dt
0 0 1

3

1

3

t0 
1

t 2

2 3

1

1  1  (9  1)  5 [C ] 2...