Challenging Engineering Problems with Detailed Answers

How many AM broadcast stations can be accommodated in a 100-kHz bandwidth if the highest frequency modulating a carrier is 5 kHz? Problem-4 A bandwidth of 20 MHz is to be considered for the transmission of AM signals. If the highest audio frequencies used to modulate the carriers are not to exceed 3 kHz, how many stations could broadcast within this band simultaneously without interfering with one another? Problem-5 The total power content of an AM signal is 1000 W. Determine the power being transmitted at the carrier frequency and at each of the sidebands when the percent modulation is 100%.
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Figure 1 shows the internal circuitry for a charger prototype. You, the development engineer, are required to do an electrical analysis of the circuit by hand to assess the operation of the charger on different loads. The two output terminals of this linear device are across the resistor, RL. You decide to reduce the complex circuit to an equivalent circuit for easier analysis. i) Find the Thevenin equivalent circuit for the network shown in Figure 1, looking into the circuit from the load terminals AB. (9 marks) R1 R2 A 40 30 20 V R4 60 B Figure 1 ii) Determine the maximum power that can be transferred to the load from the circuit. (4 marks) 10A R330 www RL
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Plot the asymptotic log magnitude curves and phase curves for the following transfer function. G(s)H(s) = 1 (2s+1)(0.5s +1)
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Figure 1 shows the internal circuitry for a charger prototype. You, the development engineer, are required to do an electrical analysis of the circuit by hand to assess the operation of the charger on different loads. The two output terminals of this linear device are across the resistor, R. You decide to reduce the complex circuit to an equivalent circuit for easier analysis. i) Find the Thevenin equivalent circuit for the network shown in Figure 1, looking into the circuit from the load terminals AB. (9 marks) R1 A R2 ww 40 30 20 V R460 RL B Figure 1 ii) Determine the maximum power that can be transferred to the load from the circuit. (4 marks) 4 10A R330
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) A microwave oven (ratings shown in Figure 2) is being supplied with a single phase 120 VAC, 60 Hz source. SAMSUNG HOUSEHOLD MICROWAVE OVEN 416 MAETANDONG, SUWON, KOREA MODEL NO. SERIAL NO. 120Vac 60Hz LISTED MW850WA 71NN800010 Kw 1.5 MICROWAVE (UL) MANUFACTURED: NOVEMBER-2000 FCC ID : A3LMW850 MADE IN KOREA SEC THIS PRODUCT COMPLIES WITH OHHS RULES 21 CFR SUBCHAPTER J Figure 2 When operating at rated conditions, a supply current of 14.7A was measured. Given that the oven is an inductive load, do the following: i) Calculate the power factor of the microwave oven. (2 marks) ii) Find the reactive power supplied by the source and draw the power triangle showing all power components. (5 marks) iii) Determine the type and value of component required to be placed in parallel with the source to improve the power factor to 0.9 leading.
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Schematic in Figure 1 shows a circuit for phone charger. (a) List all the electronics components available in the circuit (b) What is the function of the transformer? (3 marks) (c) Which components in the circuit act as a rectifier? Describe the construction of the rectifier and states its type. (3 marks) (d) With the help of waveform at the input terminal and output terminal, explain the working principle of the rectifier. AC Supply 220-240 Volts Transformer (4 marks) Figure 1: Schematic diagram of phone charger D1 D2 16T D3 D4 C1 (10 marks) 5-V Voltage Regu VIN 7805 IC GND
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You are expected to predict the transformers' performance under loading conditions for a particular installation. According to the load detail, each transformer will be loaded by 80% of its rated value at 0.8 power factor lag. If the input voltage on the high voltage side is maintained at 480 V, calculate: i) The output voltage on the secondary side (4 marks) ii) The regulation at this load (2 marks) iii) The efficiency at this load
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An example of QPSK modulator is shown in Figure 1. (b) (c) Binary input data f (d) Bit splitter Bit clock I channel f/2 Reference carrier oscillator (sin w, t) channel f/2 Balanced modulator 90phase shift Balanced modulator Bandpass filter Linear summer Bandpass filter Figure 1: QPSK Modulator (a) By using appropriate input data, demonstrate how the QPSK modulation signals are generated based from the given circuit block. Bandpass filter QPSK output Sketch the phasor and constellation diagrams for QPSK signal generated from Figure 1. Modify the circuit in Figure 1 to generate 8-PSK signals, with a proper justification on your design. Generate the truth table for your 8-PSK modulator as designed in (c).
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Figure 1 shows the internal circuitry for a charger prototype. You, the development engineer, are required to do an electrical analysis of the circuit by hand to assess the operation of the charger on different loads. The two output terminals of this linear device are across the resistor. R. You decide to reduce the complex circuit to an equivalent circuit for easier analysis. i) Find the Thevenin equivalent circuit for the network shown in Figure 1, looking into the circuit from the load terminals AB. (9 marks) A R1 ww 40 R2 ww 30 20 V R4 60 RL B Figure 1 ii) Determine the maximum power that can be transferred to the load from the circuit. (4 marks) 10A R330
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The open-loop transfer function of a unity feedback system is 5 2s+1 Determine the steady-state output of the closed-loop system due to the following input signals: r(t) = sin(t +30) G(s) =
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) For the networks of Figure 3(a), analyze the following parameters: i. Draw the load line in Figure 3(b) for the given network ii. For a Q-point at the intersection of the load line with a base current of 15 A, iii. determine the values of ICQ and VCEQ- Determine the dc beta at the Q-point. 6 5 4 3 2 1 Ic (mA) RB HH 5 www Vcc = 18 V 30 A Figure 3(a): Emitter-bias network 10 25 A 20 15 Rc 2.2 HH C Figure 3(b). Load line RE 1.1 15 A 10 . 5 A Ig = 0 MA 20 VCE
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The RLC parallel circuit is known, the input is Current source e(t)= i, (t), and output is y(t) = v(t). please give its second order differential equation and transfer function H (s). i(t) ( R R iz L ic v(t)
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. Use PSpice to find the Thevenin equivalent of the circuit shown below as seen from terminals a-b. Verify the answer with MATLAB. -j4 10 ww 40/45 V +8/0 A j5 n + ww 4
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Circuit J++ Circuit Parameters Transistor Parameters RE=15 km2 RC = 5 B=120 VEB(ON) = 0.7 V VT = 26 mV RL = 10 VEE = +10 V VA = 100 V Vcc=+10 V Type of Transistor: ? Input (vs): Terminal ? Output (vo): Terminal? Type of Amplifier Configuration: Common-? Amplifier Rc RE SETT + Vcc VEE CCI Cc2 RL 1. 2. 3. 4. 5. By stating and applying electrical circuit theory/law/principle: Sketch the large-signal (DC) equivalent circuit. Derive and Determine the Quiescent-Point (Q-Point) large-signal (DC) parameters. Sketch the small-signal (ac) equivalent circuit. Derive and Determine the small-signal (ac) parameters. If vs 100 mVp-p, sketch the input and output waveforms of the Amplifier Circuit J++.
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Using the results of Procedure 7 and Table 4.9.4, make the following ratio calculations (use the 1.2 N.m [9 lbf.in] characteristics as the full load values). a) starting current to full load b) starting torque to full load torque c) full load current to no load comment 4. The squirrel cage motor induction motor is one of the most reliable machines used in industry. Explain The squirrel cage induction motor is the most reliable machine used in the industry because they are self starting in nature and economical. They are used in both fixed speed variable speed frequency drivers. 5. If the power line frequency was 50 Hz: a) at what speed would the motor run? 8. Do the following: a) Turn on the power supply and quickly measure E1, I1 and the developed starting torque. El=213.3/209.1 Vac, I1=4.087/3.702Aac, starting torque = 2.18/3.006 N.m [lbf. in] b) Calculate the apparent power to the motor at starting torque apparent power. apparent power 1507/1344VA - I, (amps) I (amps) I, (amps) TORQUE (lbf-in) W SPEED (r WT W (amps) (amps) min) LVSIM-EMS: 0.752 0.752 0.752 SIM SIM 0 DACI:0 0.703 0.679 0.68 -27 112 Table 1 Torque results at 0 lbf-in TORQU I, (amps) I, (amps) I, (amps) W W E (lbf-in) (amps) (amps) 0 0.752 0.752 0.752 SIM SIM 3 0.763 0.763 0.763 SIM SIM 0.848 0.848 0.848 SIM SIM 0.987 0.987 0.987 SIM SIM 1.115 1.116 1.115 SIM SIM 6 9 12 1773 1781 SPEED (r/min) 1773 1767 1738 1706 1676 (W+W) 100.1 84.58 W (Wi+W) 100.1 114.3 183.4 258.2 315.7
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Sketch the high-frequency small-signal equivalent circuit of a MOS transistor. Assume that the body terminal is connected to the source. Identify (name) each parameter of the equivalent circuit. Also, write an expression for the small-signal gain vds/vgs(s) in terms of the small-signal parameters and the high-frequency cutoff frequency H. Clearly define H in terms ofthe resistance and capacitance parameters.
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Par Worksheet 13-2 16361 Name Current in Parallel Circuits 1. Current at A = mA AMMETER- A mA mA TO 90 VDC SUPPLY 2. Current at B = 3. Current at C = TO 36 VDC SUPPLY 4. Current at D = 5. Current at E = TO 12 VDC SUPPLY 6. Current at F= 7. Current at G = TO 40 VDC SUPPLY 2013 American Technical Publishers, Inc. All rights reserved B mA A O mA mA Jun 130 -R, = 2.5 k R = 30 kn R = 80 k -R = 12 k Date -R = 10 k O 13 C -R = 60 kn -R 100 kn G -R = 12 k to -R=5 kn -R=400 kn -R = 6 kn R=1.5 kn-
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A-jb d) Ja-b 6. The transfer function H(s) of a circuit is: a) the frequency-dependent ratio of a phasor output Y(s) (an element voltage or current) to a phasor input X(s) (source voltage or current). b) the frequency-dependent ratio of a phasor output X(s) (an element voltage or current) to a phasor input Y(s) (source voltage or current). c) the time-dependent ratio of a phasor output Y(s) (an element voltage or current) to a phasor input X(s) (source voltage or current). d) Nothing of the above
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Figure 1 shows the internal circuitry for a charger prototype. You, the development engineer, are required to do an electrical analysis of the circuit by hand to assess the operation of the charger on different loads. The two output terminals of this linear device are across the resistor, RL. You decide to reduce the complex circuit to an equivalent circuit for easier analysis. i) Find the Thevenin equivalent circuit for the network shown in Figure 1, looking into the circuit from the load terminals AB. (9 marks) R1 A R2 ww 40 30 20 V R460 RL B Figure 1 ii) Determine the maximum power that can be transferred to the load from the circuit. (4 marks) 10A R3 30
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The data file ecg_60hz.mat contains an ECG signal, sampled at 200 Hz, with a significant amount of 60 Hz power-line artifact. You are asked to remove the interference and make interpretation of the ECG signal using the following strategies: a. Design and draw an op-amp analog filter to remove the 60 Hz power line interference from the ECG signal. Choose appropriate cut-off frequency and determine the resistor and capacitor values. (7.5 points)
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Figure 1 shows the internal circuitry for a charger prototype. You, the development engineer, are required to do an electrical analysis of the circuit by hand to assess the operation of the charger on different loads. The two output terminals of this linear device are across the resistor, RL. You decide to reduce the complex circuit to an equivalent circuit for easier analysis. i) Find the Thevenin equivalent circuit for the network shown in Figure 1, looking into the circuit from the load terminals AB. (9 marks) R1 www 40 R2 ww 30 20 V R4 5 60 R330 B Figure 1 ii) Determine the maximum power that can be transferred to the load from the circuit. (4 marks) 10A www RL
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A balanced three-phase Y load has one phase voltage of VCN = 277
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Suppose that a system has the following transfer function: s+1 s+5s +6 G(s) = Generate the plot of the output response (for time, 1>0 and t
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Given the amplifier shown in Fig. 1. If equivalent circuit. (c) Input impedance, ri. + I RB21 82kQ2 C o+|| B RB22 43kQ2 Rc2 10kQ2 R'E2 510 RE2 7.5k T + CE C3 O 2 = 50, try to determine: (a) Q point; (b) Small signal (d) Output impedance, ro. (e) voltage gain, Au. + Ucc +24V -O + .
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