Determine the voltage drop across the resistor of Fig. if the incident flux is fc, V = V, and R = kΩ. Use the characteristics of Fig
> Design a high-isolation OR-gate employing phototransistors and LEDs.
> For a phototransistor having the characteristics of Fig. 17.50, determine the photo induced base current for a radiant flux density of 5mW/cm2. If hfe = 40, find IC.
> Given the relaxation oscillator of Fig. 17.68: a. Find RB1 and RB2 at IE = 0 A. b. Determine VP, the voltage necessary to turn on the UJT. c. Determine whether R1 is within the permissible range of values defined by Eq. (17.8). d. Determine the frequency
> Determine RC and RB for a fixed-bias configuration if VCC = 12 V, = 80, and ICQ = 2.5 mA with VCEQ = 6 V. Use standard values.
> For a unijunction transistor with VBB = 20 V, h = 0.65, RB1 = 2 kΩ (IE = 0), and VD = 0.7 V, determine: a. RB2. b. RBB. c. VRB . d. VP.
> For the network of Fig. 17.40, in which V = 40 V, h = 0.6, VV = 1 V, IV = 8 mA, and IP = 10 mA, determine the range of R1 for the triggering network.
> For the network of Fig. 17.33, if C = 1 mF, find the level of R that will result in a 50% conduction period for the load in either direction if the turn-on voltage for the diac in either direction is 12 V and the applied sinusoidal signal has a peak valu
> Find the level of human body capacitance Cb that would result in a 45-degree phase shift between vi and vG for the network of Fig. 17.30.
> If VBR2 is 6.4 V, determine the range for VBR1 using Eq. (17.1).
> For the network of Fig. 17.28, if VBR = 6 V, V = 40 V, R = 10 kΩ, C = 0.2 mF, and VGK (firing potential) = 3 V, determine the time period between energizing the network and the turning on of the SCR.
> a. Using Fig. 17.24b, determine the minimum irradiance required to fire the device at room temperature (25°C). b. What percentage reduction in irradiance is allowable if the junction temperature is increased from 0°C (32°F) to 100°C (212°F)?
> a. In Fig. 17.22, if V= 50 V, determine the maximum possible value the capacitor C1 can charge to (VGK ÷ 0.7 V). b. Determine the approximate discharge time (5t) for R3 = 20 kΩ. c. Determine the internal resistance of the GTO if the rise time is one-ha
> For the network of Fig. 17.19 a. Write an equation for the voltage from gate to ground for the SCR. b. What is the voltage VGK when RS = R'? c. Find RS to establish a turn-on voltage of 2 V if R' = 10 kΩ. d. When the alarm turns on, what is the current t
> What is the suggested turn-off procedure for the network of Fig. 17.18?
> Given VC = 8 V for the network of Fig. 4.140, determine: a. IB. b. IC. c. d. VCE.
> What is the reactance of a 10@mF capacitor at a frequency of 1 kHz? For networks in which the resistor levels are typically in the kilohm range, is it a good assumption to use the short-circuit equivalence for the conditions just described? How about at
> Refer to the emergency-lighting system of Fig. 17.14. a. Sketch the waveform of the full-wave rectified signal across the bulb using a drop of 0.7 V during conduction of each diode. b. Determine the peak voltage across the capacitor C1 when the SCR1 is o
> a. For a varicap diode having the characteristics of Fig. determine the difference in capacitance between reverse-bias potentials of — V and — V. b. Determine the incremental rate of change (ΔC>ΔVr) at V = —8 V. How does this value compare with
> a. Determine the transition capacitance of a diffused junction varicap diode at a reverse potential of V if C(0) = pF and Vr = V. b. From the information of part (a), determine the constant K in Eq. (16.2).
> Using the characteristics of Fig(c), determine the reactance of the diode capacitor at a frequency of MHz and a reverse bias potential of V. Is it significant?
> Using the plot of Fig. a, a. What is the forward voltage at a current of mA (note the log scale) at room temperature (°C). b. What is the forward voltage at the same current as part (a) but a temperature of °C? c. What can be said about the e
> Determine the frequency of oscillation for the network of Fig. 16.50 if L = 5 mH, Rl = 10 Ω, and C = 1 mF.
> For E = 0.5 V and R = 51 Ω, sketch vT for the network of Fig. 16.49 and the tunnel diode of Fig. 16.44.
> Determine the stable operating points for the network of Fig. 16.48 if E = 2 V, R = 0.39 kΩ, and the tunnel diode of Fig. 16.44 is employed.
> Determine the negative resistance for the tunnel diode of Fig. 16.44 between VT = 0.1 V and VT = 0.3 V.
> Why do you believe the maximum reverse current rating for the tunnel diode can be greater than the forward current rating? (Hint: Note the characteristics and consider the power rating.)
> For the network of Fig. 4.139, determine: a. IB. b. IC. c. VE. d. VCE.
> Note in the equivalent circuit of Fig. 16.45 that the capacitor appears in parallel with the nega- tive resistance. Determine the reactance of the capacitor at 1 MHz and 100 MHz if C = 5 pF, and determine the total impedance of the parallel combination (
> What are the essential differences between a semiconductor junction diode and a tunnel diode?
> In Fig. 16.43, V = 0.2 V and Rvariable = 10 Ω. If the current through the sensitive movement is 2 mA and the voltage drop across the movement is 0 V, what is the resistance of the thermistor?
> a. Referring to Fig. 16.41, determine the current at which a 25°C sample of the material changes from a positive to a negative temperature coefficient. (Figure 16.41 is a log scale.) b. Determine the power and resistance levels of the device (Fig. 16.41)
> Using the information provided in Fig. 16.40, determine the total resistance of a 2-cm length of the material having a perpendicular surface area of 1 cm2 at a temperature of 0°C. Note the vertical log scale.
> For the thermistor of Fig. 16.40, determine the dynamic rate of change in specific resistance with temperature at T = 20°C. How does this compare to the value determined at T = 300°C? From the results, determine whether the greatest change in resistance
> What are the relative advantages and disadvantages of an LCD display as compared to an LED display?
> Discuss the relative differences in mode of operation between an LED and an LCD display.
> Referring to Fig. 16.35, which terminals must be energized to display number 7?
> If 60 mA of dc forward current is applied to an SG1010A IR emitter, what will be the incident radiant flux in lumens 5° off the center if the package has an internal collimating system? Refer to Figs. 16.30 and 16.31.
> For the common-base network of Fig. 4.138 a. Using the information provided determine the value of RC. b. Find the currents IB and IE. c. Determine the voltages VBC and VCE.
> a. Through the use of Fig. 16.31, determine the relative radiant intensity at an angle of 25° for a package with a flat glass window. b. Plot a curve of relative radiant intensity versus degrees for the flat package.
> a. Determine the radiant flux at a dc forward current of 70 mA for the device of Fig. 16.30. b. Determine the radiant flux in lumens at a dc forward current of 45 mA.
> Which colors is the CdS unit of Fig. 16.27 most sensitive to?
> Using the data of Fig determine the reverse leakage current at a temperature of C. Assume a linear relationship between the two quantities.
> a. Sketch a curve of rise time versus illumination using the data from Fig. 16.27. b. Repeat part (a) for the decay time. c. Discuss any noticeable effects of illumination in parts (a) and (b).
> Using the data provided in Fig. 16.27, sketch a curve of percentage conductance versus temperature for 0.01, 1.0, and 100 fc. Are there any noticeable effects?
> If the illumination on the photoconductive diode in Fig. 16.28 is fc, determine the magnitude of Vi to establish 6 V across the cell if R1 is equal to 5 kΩ. Use the characteristics of Fig. 16.26.
> What is the “dark current” of a photodiode?
> What is the approximate rate of change of resistance with illumination for a photoconductive cell with the characteristics of Fig. for the ranges (a) S kΩ, (b) S kΩ, and (c) S kΩ? (Note that this is a log scale.) Which region has t
> Write an equation for the diode current of Fig. versus the applied light intensity in foot-candles.
> For the network of Fig. 4.137, determine: a. IE. b. VC. c. VCE.
> Referring to Fig. , determine Il if Vl = V and the light intensity is W/m2.
> What is the energy in joules associated with photons that have a wavelength matching that of the color blue in the visible spectrum? Repeat part (a) for the color red. Do the results confirm the fact that the shorter the wavelength the higher the energy
> a. Plot the-V curve for the same solar cell of Fig. but with a light intensity of fc1. b. Plot the resulting power curve from the results of part (a). c. What is the maximum power rating? How dews it compares to the maximum power rating for a li
> a. Consult Fig. Compare the dynamic resistances of the diodes in the forward-bias regions. b. How do the levels of Is and VZ compare?
> a. For the solar cell of Fig. 16.14, determine the ratio ΔIVOC>Δfc for the range of 20 fc to 100 fc if fc1 = 40fc. b. Using the results of part (a), determine the expected level of VOC at a light intensity of 60 fc.
> a. For the solar cell of Fig. , determine the ratio ΔISC>Δfc if fc1 = fc. b. Using the results of part (a), find the level of ISC resulting from a light intensity of foot candles.
> If the power rating of a solar cell is determined on a very rough scale by the product VOC ISC, is the greatest rate of increase obtained at lower or higher levels of illumination? Explain your reasoning.
> A 1-cm by -cm solar cell has a conversion efficiency of %. Determine the maximum power rating of the device.
> Referring to Fig. 16.11, if VDD = V for the varactor of Fig find the resonant frequency of the tank circuit if CC = pF and LT = mH.
> For the network of Fig. 4.136, determine: a. IB. b. IC. c. VCE. d. VC.
> Using Figa, compare the Q levels at a reverse bias potential of V and V. What is the ratio between the two? If the resonant frequency is 10 MHz, what is the bandwidth for each bias voltage? Compare the bandwidths obtained and compare their ra
> What region of VR would appear to have the greatest change in capacitance per change in reverse voltage for the diode of Fig. ? Be aware that it is a log-log scale. Then, for this region, determine the ratio of the change in capacitance to the chang
> Determine T1 for a varactor diode if C0 = 22 pF, TCC = 0.02%/ °C, and ΔC = 0.11 pF due to an increase in temperature above T0 = 25°C.
> At a reverse-bias potential of 4 V, determine the total capacitance for the varactor from Fig. a and calculate the Q value from Q = 1> (pf RS Ct) using a frequency of 10 MHz and Rs = Ω. Compare to the Q value determined from the chart of Fig
> Using Fig. a, determine the total capacitance at a reverse potential of V and 8 V and find the tuning ratio between these two levels. How does it compare to the tuning ratio for the ratio between reverse bias potentials of V and V?
> A full-wave rectifier (operating from a-Hz supply) drives a capacitor-filter circuit (C = mF), which develops V dc when connected to a -kΩ load. Calculate the output voltage ripple.
> A full-wave rectifier operating from the Hz ac supply produces a-V peak rectified voltage. If a-mF capacitor is used, calculate the ripple at a load of mA.
> A full-wave rectified voltage of V peak is connected to a@mF filter capacitor. What are the ripple and dc voltages across the capacitor at a load of mA?
> A full-wave rectified signal of V peak is fed into a capacitor filter. What is the voltage regulation of the filter if the output is V dc at full load?
> A simple capacitor filter fed by a full-wave rectifier develops V dc at ripple factor. What is the output ripple voltage (rms)?
> For the emitter follower network of Fig. 4.135 a. Find IB, IC, and IE. b. Determine VB, VC, and VE. c. Calculate VBC and VCE.
> What is the rms ripple voltage of a full-wave rectifier with output voltage 8 V dc?
> A half-wave rectifier develops V dc. What is the value of the ripple voltage?
> Determine the regulated output voltage from the circuit of Fig. 
> Determine the regulated voltage in the circuit of Fig.  with R1 =  Ω and R2 = ï€
> Determine the maximum value of load current at which regulation is maintained for the circuit of Fig. 
> Calculate the minimum input voltage of the full-wave rectifier and filter capacitor network in Fig. ï€±ï€µï€®ï€´ï€¶ï€ when connected to a load drawing ï
> Draw the circuit of a voltage supply comprised of a full-wave bridge rectifier, capacitor filter, and IC regulator to provide an output of + V.
> Determine the regulated voltage and circuit currents for the shunt regulator of Fig. .
> Calculate the regulated output voltage in the circuit of Fig. 
> What regulated output voltage results in the circuit of Fig. ?
> Determine the level of VE and IE for the network of Fig. 4.134.
> A filter circuit provides an output of V unloaded and V under full-load operation. Calculate the percentage voltage regulation.
> Calculate the output voltage and Zener diode current in the regulator circuit of Fig. 
> If the no-load output voltage for Problem 17 is V, calculate the percentage voltage regulation with a -kΩ load.
> Calculate the rms ripple voltage at the output of an RC filter section that feeds a @kΩ load when the filter input is V dc with -V rms ripple from a full-wave rectifier and capacitor filter. The RC filter section components are R = Ω and C =
> A simple capacitor filter has an input of V dc. If this voltage is fed through an RC filter section (R = Ω, C = mF), what is the load current for a load resistance of Ω?
> An RC filter stage (R = Ω, C = mF) is used to filter a signal of V dc with V rms operating from a full-wave rectifier. Calculate the percentage ripple at the output of the RC section for a-mA load. Also calculate the ripple of the filtere
> An RC filter stage is added after a capacitor filter to reduce the percentage of ripple to Calculate the ripple voltage at the output of the RC filter stage providing V dc.
> Calculate the percentage ripple for the voltage developed across a -mF filter capacitor when providing a load current of mA. The full-wave rectifier operating from the -Hz supply develops a peak rectified voltage of V.
> Calculate the size of the filter capacitor needed to obtain a filtered voltage with % ripple at a load of mA. The full-wave rectified voltage is V dc and the supply is Hz.
> A -mF capacitor provides a load current of mA at 8% ripple. Calculate the peak rectified voltage obtained from the -Hz supply and the dc voltage across the filter capacitor.
> Given VB = 4 V for the network of Fig. 4.133, determine: a. VE. b. IC. c. VC. d. VCE. e. IB. f. 
> Calculate the size of the filter capacitor needed to obtain a filtered voltage having % ripple at a load of mA. The full-wave rectified voltage is V dc, and the supply is Hz.
> What is the ripple factor of a sinusoidal signal having peak ripple of 2 V on an average of 50 V?
> For an FET Colpitts oscillator as in Fig. 14.26 and the following circuit values determine the circuit oscillation frequency:
> Calculate the frequency of a Wien bridge oscillator circuit (as in Fig. 14.23) when R = 10 kΩ and C = 2400 pF.
> Calculate the operating frequency of a BJT phase-shift oscillator as in Fig. 14.21b for R = 6 kΩ, C = 1500 pF, and RC = 18 kΩ.
> An FET phase-shift oscillator having gm = 6000 mS, rd = 36 kΩ, and feedback resistor R = 12 kΩ is to operate at 2.5 kHz. Select C for specified oscillator operation.
> For a circuit as in Fig. 14.11 and the following circuit values, calculate the circuit gain and the input and output impedances with and without feedback: RB = 600 kΩ, RE = 1.2 kΩ, RC = 4.7 kΩ, and b = 75. Use VCC = 16 V.
> Calculate the gain with and without feedback for an FET amplifier as in Fig. 14.7 for circuit values R1 = 800 kΩ, R2 = 200 Ω, Ro = 40 kΩ, RD = 8 kΩ, and gm = 5000 mS.
