Determine the level of Vo for each network of Fig. 2.157.
> Refer to Figure 10.50. Given: q1 = 10.9 kN/m x1 = 2.45 m x2 = 1.22 m z = 0.9 m If the vertical stress at point A due to the loading is 1.7 kN/m2, determine the magnitude of q2.
> A soil element is shown in Figure 10.43. Determine the following. Maximum and minimum principal stresses Normal and shear stresses on the plane AB Use Eqs. (10.3), (10.4), (10.6), and (10.7).
> A soil has e = 0.75, w = 21.5%, and Gs = 2.71. Determine: Moist unit weight (lb/ft3) Dry unit weight (lb/ft3) Degree of saturation (%)
> Refer to Figure 9.5a. Given: H1 = 1 m, H2 = 2 m, h = 1.2 m, void ratio of sand (e) = 0.55, specific gravity of soil solids (Gs) = 2.68, area of the tank = 0.5 m2 , and hydraulic conductivity of sand = 0.1 cm/s. What is the rate of upward seepage? If h 5
> Refer to Figure 9.5a. If H1 = 0.6 m, H2 = 1 m, h 5 0.4 m, sat = 18.6 kN/m3 , hydraulic conductivity of sand (k) = 0.12 cm/s, and area of tank = 0.45 m2 , what is the rate of upward seepage of the water (m3 /min)?
> Refer to Problem 9.6. It is required to make an open excavation of 18 ft in the saturated clay. To avoid heaving, the cut will be filled with water similar to that shown in Figure 9.6. What should be the height of water, h, in the excavation?
> An exploratory drill hole was made in a stiff saturated clay (see Figure 9.28). The sand underlying the clay was observed to be under artesian pressure. Water in the drill hole rose to a height of 18 ft above the top of the sand layer. If an open excavat
> A sand has Gs = 2.68. Calculate the hydraulic gradient that will cause boiling for e = 0.4, 0.5, 0.6, and 0.7. Plot a graph for icr versus e.
> Refer to the soil profile shown in Figure 9.27. Calculate the variation of , u, and ’ with depth. If the water table rises to the top of the ground surface, what is the change in the effective stres
> Refer to Figure 9.26. Calculate , u, and ’ at A, B, C, and D for the following cases, and plot the variations with depth. (Note: e = void ratio,  = moisture content, Gs = specific
> Refer to Figure 9.26. Calculate , u, and ’ at A, B, C, and D for the following cases, and plot the variations with depth. (Note: e = void ratio,  = moisture content, Gs = specific
> Figure 9.31 shows a concrete dam. Consider Case 1 without the sheet pile and Case 2 with the sheet pile along the upstream side. Draw flow nets for both cases. Determine the value of q/k for both cases. (Note: q= m3/s/m; k = m/s.) Determine the factor of
> Determine the factor of safety against heave on the downstream side of the single-row sheet pile structure shown in Figure 9.30. Use the following soil and design parameters: H1 = 7 m, H2 = 3 m, thickness of permeable layer (T) = 12 m, design depth of pe
> Results of a sieve analysis for Soils A, B, and C are given below. To obtain a more representative sample for further geotechnical testing, a ternary blend was created by uniformly mixing 8000 kg of each soil. If a sieve analysis is conducted on the mi
> Repeat Problem 2.3 with the following data.
> Design a clamper to perform the function indicated in Fig. 2.184.
> For the network of Fig. 2.183: a. Calculate 5t. b. Compare 5t to half the period of the applied signal. c. Sketch vo.
> Sketch vo for each network of Fig. 2.182 for the input shown.
> Sketch vo for each network of Fig. 2.181 for the input shown.
> Sketch iR and vo for the network of Fig. 2.180 for the input shown.
> Determine vo for each network of Fig. 2.179 for the input shown.
> Determine vo for each network of Fig. 2.178 for the input shown.
> Determine vo for each network of Fig. 2.177 for the input shown.
> Determine vo for each network of Fig. 2.176 for the input shown.
> Sketch vo for the network of Fig. 2.175 and determine the dc voltage available.
> Describe the difference between majority and minority carriers.
> Sketch vo for the network of Fig. 2.174 and determine the dc voltage available.
> Determine vo and the required PIV rating of each diode for the configuration of Fig. 2.173. In addition, determine the maximum current through each diode.
> A full-wave bridge rectifier with a 120-V rms sinusoidal input has a load resistor of 1 kΩ. a. If silicon diodes are employed, what is the dc voltage available at the load? b. Determine the required PIV rating of each diode. c. Find the maximum current t
> a. Given Pmax = 14 mW for each diode at Fig. 2.172, determine the maximum current rating of each diode (using the approximate equivalent model). b. Determine Imax for the parallel diodes. c. Determine the current through each diode at Vimax using the res
> For the network of Fig. 2.171, sketch vo and iR.
> For the network of Fig. 2.170, sketch vo and determine Vdc.
> Repeat Problem 22 with a 10 kΩ load applied as shown in Fig. 2.169. Sketch vL and iL.
> Repeat Problem 22 with a silicon diode (VK = 0.7 V).
> Assuming an ideal diode, sketch vi, vd, and id for the half-wave rectifier of Fig. 2.168. The input is a sinusoidal waveform with a frequency of 60 Hz. Determine the profit value of vi from the given dc level.
> Determine Vo for the configuration of Fig. 2.167.
> Describe the difference between donor and acceptor impurities.
> Determine the level of Vo for the gate of Fig. 2.166.
> Determine Vo for the negative logic AND gate of Fig. 2.165.
> Determine Vo for the negative logic OR gate of Fig. 2.164.
> Determine Vo for the network of Fig. 2.42 with 10 V on both inputs.
> Determine Vo for the network of Fig. 2.42 with 0 V on both inputs.
> Determine Vo for the network of Fig. 2.39 with 10 V on both inputs.
> Determine Vo for the network of Fig. 2.39 with 0 V on both inputs.
> Determine Vo and I for the networks of Fig. 2.161.
> Determine Vo and ID for the networks of Fig. 2.160.
> Determine Vo1 and Vo2 for the networks of Fig. 2.159.
> Describe the difference between n-type and p-type semiconductor materials.
> Determine Vo and ID for the networks of Fig. 2.158.
> Determine Vo and ID for the networks of Fig. 2.156.
> Determine the current I for each of the configurations of Fig. 2.155 using the approximate equivalent model for the diode. FIG. 2.155 Problem 5.
> a. Using the approximate characteristics for the Si diode, determine VD, ID, and VR for the circuit of Fig. 2.154. b. Perform the same analysis as part (a) using the ideal model for the diode. c. Do the results obtained in parts (a) and (b) suggest that
> Sketch the current derating curve for the average forward current of the high-efficiency red LED of Fig. 1.52 as determined by temperature. (Note the absolute maximum ratings.)
> a. If the luminous intensity at 0° angular displacement is 3.0 mcd for the device of Fig. 1.52, at what angle will it be 0.75 mcd? b. At what angle does the loss of luminous intensity drop below the 50% level?
> a. What is the percentage increase in relative efficiency of the device of Fig. 1.52 if the peak current is increased from 5 mA to 10 mA? b. Repeat part (a) for 30 mA to 35 mA (the same increase in current). c. Compare the percentage increase from parts
> Using the information provided in Fig. 1.52, determine the forward voltage across the diode if the relative luminous intensity is l.5.
> Given that Eg = 0.67 eV for germanium, find the wavelength of peak solar response for the material. Do the photons at this wavelength have a lower or higher energy level?
> Consult your reference library and determine the level of Eg for GaP, ZnS, and GaAsP, three semi- conductor materials of practical value. In addition, determine the written name for each material.
> Referring to Fig. 1.52e, what would appear to be an appropriate value of VK for this device? How does it compare to the value of VK for silicon and germanium?
> Compare the levels of dynamic impedance for the 24-V diode of Fig. 1.48b at current levels of 0.2, 1, and 10 mA. How do the results relate to the shape of the characteristics in this region?
> Determine the dynamic impedance for the 24-V diode at IZ = 10 mA for Fig. 1.48b. Note that it is a log scale.
> Using the curves of Fig. 1.48a, what level of temperature coefficient would you expect for a 20-V diode? Repeat for a 5-V diode. Assume a linear scale between nominal voltage levels and a current level of 0.1 mA.
> Determine the temperature coefficient of a 5-V Zener diode (rated 25°C value) if the nominal voltage drops to 4.8 V at a temperature of 100°C.
> At what temperature will the 10-V Zener diode of Fig. 1.47 have a nominal voltage of 10.75 V? (Note the data in Table 1.7.)
> The following characteristics are specified for a particular Zener diode: VZ = 29 V, VR = 16.8 V, IZT = 10 mA, IR = 20 mA, and IZM = 40 mA. Sketch the characteristic curve in the manner displayed in Fig. 1.47.
> Using the characteristics of Fig. 1.37, determine the temperature at which the diode current will be 50% of its value at room temperature (25°C).
> Using the characteristics of Fig. 1.37, determine the maximum power dissipation levels for the diode at room temperature (25°C) and 100°C. Assuming that VF remains fixed at 0.7 V, how has the maximum level of IF changed between the two temperature levels
> For the diode of Fig. 1.37, determine the maximum ac (dynamic) resistance at a forward cur- rent of 0.1, 1.5, and 20 mA. Compare levels and comment on whether the results support con- clusions derived in earlier sections of this chapter.
> If 48 eV of energy is required to move a charge through a potential difference of 3.2 V, deter- mine the charge involved.
> For the diode of Fig. 1.37 determine the level of IR at room temperature (25°C) and the boiling point of water (100°C). Is the change significant? Does the level just about double for every 10°C increase in temperature?
> Does the reverse saturation current of the diode of Fig. 1.37 change significantly in magnitude for reverse-bias potentials in the range —25 V to —100 V?
> a. Comment on the change in capacitance level with increase in reverse-bias potential for the diode of Fig. 1.37. b. What is the level of C(0)? c. Using VK = 0.7 V, find the level of n in Eq. 1.9.
> Plot IF versus VF using linear scales for the diode of Fig. 1.37. Note that the provided graph employs a log scale for the vertical axis (log scales are covered in Sections 9.2 and 9.3).
> Sketch the waveform for i of the network of Fig. 1.57 if tt = 2ts and the total reverse recovery time is 9 ns. FIG. 1.57 Problem 45.
> Find the applied reverse bias potential if the transition capacitance of a silicon diode is 4 pF but the no-bias level is 10 pF with n = 1>3 and VK = 0.7 V.
> The no-bias transition capacitance of a silicon diode is 8 pF with VK = 0.7 V and n = 1>2. What is the transition capacitance if the applied reverse bias potential is 5 V?
> Determine the reactance offered by a diode described by the characteristics of Fig. 1.33 at a forward potential of 0.2 V and a reverse potential of —20 V if the applied frequency is 6 MHz.
> Describe in your own words how diffusion and transition capacitances differ.
> Referring to Fig. 1.33, determine the diffusion capacitance at 0 V and 0.25 V.
> a. How much energy in joules is required to move a charge of 12 mC through a difference in potential of 6 V? b. For part (a), find the energy in electron-volts.
> a. Referring to Fig. 1.33, determine the transition capacitance at reverse-bias potentials of —25 V and —10 V. What is the ratio of the change in capacitance to the change in voltage? b. Repeat part (a) for reverse-bias potentials of —10 V and —1 V. D
> Find the piecewise-linear equivalent circuit for the germanium and gallium arsenide diodes of Fig. 1.18.
> Repeat Problem 36 for the diode of Fig. 1.27.
> Find the piecewise-linear equivalent circuit for the diode of Fig. 1.15. Use a straight-line seg- ment that intersects the horizontal axis at 0.7 V and best approximates the curve for the region greater than 0.7 V.
> Determine the ac resistance for the diode of Fig. 1.15 at 0.75 V and compare it to the average ac resistance obtained in Problem 34.
> Determine the average ac resistance for the diode of Fig. 1.15 for the region between 0.6 V and 0.9 V.
> Using Eq. (1.6), determine the ac resistance at a current of 1 mA and 15 mA for the diode of Fig. 1.15. Modify the equation as necessary for low levels of diode current. Compare to the solutions obtained in Problem 32.
> Using Eq. (1.5), determine the ac resistance at a current of 1 mA and 15 mA for the diode of Fig. 1.15. Compare the solutions and develop a general conclusion regarding the ac resistance and increasing levels of diode current.
> a. Determine the dynamic (ac) resistance of the commercially available diode of Fig. 1.15 at a forward current of 10 mA using Eq. (1.5). b. Determine the dynamic (ac) resistance of the diode of Fig. 1.15 at a forward current of 10 mA using Eq. (1.6). c.
> Calculate the dc and ac resistances for the diode of Fig. 1.15 at a forward current of 10 mA and compare their magnitudes.
> Determine the value of R for the circuit of Fig. 2.153 that will result in a diode current of 10 mA if E = 7 V. Use the characteristics of Fig. 2.152b for the diode.
> Determine the static or dc resistance of the commercially available diode of Fig. 1.15 at a reverse voltage of —10 V. How does it compare to the value determined at a reverse voltage of —30 V?
> Repeat Problem 27 at a forward current of 15 mA and compare results.
> Determine the static or dc resistance of the commercially available diode of Fig. 1.15 at a for- ward current of 4 mA.
> What is the one important difference between the characteristics of a simple switch and those of an ideal diode?
> Describe in your own words the characteristics of the ideal diode and how they determine the on and off states of the device. That is, describe why the short-circuit and open-circuit equiva- lents are appropriate.
> Describe in your own words the meaning of the word ideal as applied to a device or a system.
> Determine the forward voltage drop across the diode whose characteristics appear in Fig. 1.19 at temperatures of —75°C, 25°C, 125°C and a current of 10 mA. For each temperature, determine the level of saturation current. Compare the extremes of each and
> Compare the characteristics of a silicon and a germanium diode and determine which you would prefer to use for most practical applications. Give some details. Refer to a manufacturer’s listing and compare the characteristics of a germanium and a silicon
> In the reverse-bias region the saturation current of a silicon diode is about 0.1 mA (T = 20°C). Determine its approximate value if the temperature is increased 40°C.
