circuits test 2

Ch10 q1

A. Time constant(tau or T) = R*C=10,000Ohms*(10×10^-6)F = 0.1 Seconds

B. V_c=V(1-e^(-t/Tau)) = 20(1-e^-t/.1)

C. t1 =12.64 t3=19 t5=19.17

D.  i_c = V/R e^-t/Tau= (20/10000) * e^-t/Tau

• v_r = V*e^-t/Tau = 20*e^-t/.1

E. voltage starts at zero, and levels off at the supply voltage. The current starts at the max(2mA) and reduces to zero

Ch10 q2

Capacitors in parallel add together, and 6+4=10 and 8+12=20. Next capacitors in series equal the product of the capacitance, over the sum, and (10×20)/10+20 = 6.667mF

ch11 p1

A. Tau = L/R = 20,000/(470×10^-6)=23.5×10^-6s

B.first determine max current i_max=V/R = 40/20000 = 2mA

• i_l= i_max*(1-e^-t/Tau)=.002(1-e^-t/Tau)

C.

• v_{l= V*e}^-t/Tau

• v_{r= V*(1-e}^-t/Tau)

D. Il 1t1.264 3t=1.9 5t=1.986mA

vl: 1t=14.72V 3t=1.96V 5V=.28V

E. Current starts at zero, and goes the max value, the voltage starts at the max and goes to zero.

Ch11 p2

10.77mH

4+5 in series, then in Parallel with 3, in series with 2,in Parallel with 1, and in series with 6.

1. Name six equipment that depend on magnetic effects to function
properly?(ch12 q1)

Motors, generators, transformers,
loudspeakers, relays, medical equipment
depend on magnetic effects to function
properly.

What is a hysteresis curve?(ch12 q2)

A typical curve of flux density B versus the magnetizing force H (hysteresis curve) is shown in Fig. 12.5.

What makes it possible to create permanent magnets?(ch12 q3)

he flux density BR which remains when the magnetizing force is zero, is called the residual flux density.
• It is this residual flux density that makes it possible to create permanent magnets.

What is the most widespread use of a Hall Effect sensor?(ch12 q4)

The most widespread application is a trigger for an alarm in large department stores, where theft is often a difficult
problem

What does Magnetic Resonance Imaging (MRI) provide?(ch12 q5)

Magnetic resonance imaging (MRI) provides quality cross sectional images of a body for medical diagnosis
and treatment.

ch13 q1

The vertical and horizontal sensitivity below the graph indicate how much each division of the graph is in the vertical and horizontal direction.

A. 28mV(Highest value the function attains)

B56mV(difference between top and bottom)

C.10microSeconds(time between peaks of the function)

D. 1/(10×10^-6)seconds = 100000Hz

E. 5

Ch13 q2

Wave functions are written as A*sin(ωt) Where A is the amplitude, and ω is 2*pi*frequency

A. A=20 ω=377/2pi = 60.00Hz

B. A=12 ω=2pi120/2pi = 120Hz

C. A=10⁶ ω= 10000/2pi1591.55Hz

D. A=8 ω=10058/2pi = 1600.78Hz

ch14q1

v_l=V_m*sin(wt+90)

A. X_l= wL = 100*.1 = 10Ohms

. V_m=A*X_l=10×10 = 100

. 100sin(100t + 90)

B. X_l=wL = 400*.1 = 40Ohms

. V_m=A*X_l= (5×10^-6)*40 = (2×10^-4)

.(2×10^-4) sin( 400t + 110)

ch14 q2

I_c=I_msin(wt+90)

I_m=A/X_c

X_c=1/wC

A. X_c = 1/200*(1×10^-6) = 500Ohms

. I_m=30/5000 = .006Amps

. I_c =0.006sin(200t+90)

B. X_c = 1/377×1×10^-6 = 265.252

I_m = (60×10^-3)/2652.52 = (2.26×10^-5)

I_c=(2.26×10^-4)sin(377t+90)

Ch14 q3

PF = Watts / (Volts*amps)

100/(150×2)  1/3

0/(150×2) = 0

300/(150×2) = 1

Ch15 q1

A. sqrt(32) < -45 degrees = Z_t

B. X_lpoints straight up, x_rpoins to the left, X_C points straight down

C. X_c = 1/wc     10=1/377c     c=1/3770=265microFarads

.    X_l =wl       6=377l   l=6/377 L=.0016H

d.E=V_max / sqrt(2) = 50<0 degrees I=E/Z_t = 8.83<45 deg

V_x=I*X_element

V_r=

V_c=

V_l=

E. V_l leads current by 90degrees

V_r is in phase with current

V_c lags current by 90 degrees

H. Fp = cos(-45) = 0.707, leading because X_c >X_l

ch16

A. Z_rl= (ZR*ZL)/ZR+ZL

     Z_rc = (ZR*ZC)/ZR+ZL

        Z_T=Zrl*Zrc/Zrl+Zrc = 65.2W<32.91

D. E/Z_t = 12/ 65.2<32.91 = .184A<32.91

E.  V/Z_c=12/(60< -90)=.2A<90

F.e=(20*sqrt(2))sin(wt)

    i=(20/X_t)sin(wt-32.63)

g. Fp=cos(32.9)= 0.842,lagging

ch17

A. Zrc=9.1-12j

Zt=19.86<37.2

B I=E/Zt = 3.02 < -37.2

C I2 = I*Zl/(Z1+Z2) = 3.98A<52.8

D. Vc = ZcE/Zt = 47.81V < -37.2

e P = V*I cosTheta = 60×3.02 *cos(37.2)=144.33W

ch18 q1

5.15A< -24.5, write equations for KVL, then solve system of equations