Questions and Answers of Electronics Fundamentals A Systems Approach

In Figure 6–85, what is the current through R2? FIGURE 6-85 + . 1 V R₁ 파 100 2 + R2 562 1.5V R3 27 2
In Figure 6–85, use the superposition theorem to find the current in R3. FIGURE 6-85 + 1 1 V R₁ 100 Ω + R₂ 56 Ω 1.5 V www R3 2702
Determine the value of a load resistor connected between terminals A and B in Figure 6–82 for maximum power transfer to the load resistor. 15 V + FIGURE 6-82 R₁ 100 ΚΩ R₂ 22 ΚΩ Ο Α -O B
Determine the voltage and current for RL in Figure 6–84. FIGURE 6-84 Vs 5V + Air R₁ 1.0 ΚΩ R34 2.2 ΚΩ RL 4.7 ΚΩ R₂ 2.2 ΚΩ τ B R4 1.5 ΚΩ
For each circuit in Figure 6–83, determine the Thevenin equivalent as seen from terminals A and B.Data in Figure 6–83, 2.5 V (2) R 100 R3 47 R4 22 R 78 A RL (b) R 100 + RL B 3V F R 270
Reduce the circuit in Figure 6–82 to its Thevenin equivalent as viewed from terminals A and B. 15 V FIGURE 6-82 R 100 R 22 B
If a DMM with 10 MΩ input resistance is used instead of the VOM in Problem 21, what percentage of the source voltage will be measured by the DMM?Data in Problem 21A 10,000 Ω/V VOM is used on the 10
A certain voltage divider consists of three 1.0 MΩ resistors connected in series to a 100 V source. Determine the voltage across one of the resistors measured by a 10 MΩ voltmeter.
In Figure 6–78, determine the current drain on the battery with no load on the output terminals. With a 10 kΩ load, what is the current from the battery?Data in Figure 6–78. 22 V FIGURE
Across which one of the following resistances will a voltmeter with a 10 MΩ internal resistance present the minimum load on a circuit?(a) 100 kΩ (b) 1.2 MΩ(c) 22 kΩ(d) 8.2 MΩ
Which will cause a smaller decrease in output voltage for a given voltage divider, a 10 kΩ load or a 56 kΩ load?
In Figure 6–77, determine the current through R4 for VAB = 6 V. R₁ 10 ΚΩ ΦΑ 9 B FIGURE 6-77 R₂ 2.7 ΚΩ R3 3.3 ΚΩ R4 Μ 4.7 ΚΩ R5 • 4.7 ΚΩ
A 12 V battery output is divided down to obtain two output voltages. Three 3.3 kΩ resistors are used to provide the two outputs with only one output at a time loaded with 10 kΩ. Determine the
In Figure 6–77, determine the current through R2 for VAB = 6 V.Data in Figure 6–77 R 10 & 9 B FIGURE 6-77 R 2.7 R3 3.3 R4 4.7 R5 4.7
In Figure 6–77, find the following: (a) Total resistance between terminals A and B.(b) Total current drawn from a 6 V source connected from A to B.(c) Current through R5 (d) Voltage
Determine the current through each resistor in both circuits of Figure 6–75; then calculate each voltage drop. + 1.5v (a) 1 R 56 R4 22 FIGURE 6-75 R 100 3 R3 100 3V (b) Alli I WI R 680
Determine the current through each resistor in Figure 6–74; then calculate each voltage drop.Data in Figure 6–74. Vs Air | | R₁ Μ 10 Ω R5 Μ 10 Ω FIGURE 6-74 R₂ 33 Ω R3 33 Ω R4 33 Ω
Choose the correct value of resistance to get the current values indicated in each circuit of Figure 3–31.Data in Figure 3–31. 8V (a) * R 싸 2A FIGURE 3-31 12 V (b) * R 4 mA H|₁ 30
The current in a circuit is 1 A. Determine what the current will be when.(a) The voltage is tripled (b) The voltage is reduced by 80% (c) The voltage is increased by 50%,
The current in a circuit is 100 mA. Determine what the current will be when (a) The resistance is increased by 100%.(b) The resistance is reduced by 30% (c) The resistance is quadrupled.
The current in a circuit is 10 mA. What will the current be if the voltage is tripled and the resistance is doubled?
A resistor is connected across the terminals of a dc voltage source in each part of Figure 3–29. Determine the current in each resistor.Data in Figure 3–29, +25.0 OFF O 10 A Hz RANGE AUTORANGE
A 5-band resistor is connected across a 12 V source. Determine the current if the resistor color code is orange, violet, yellow, gold, brown.
A 10 Ω resistor is connected across a 12 V battery. How much current is there through the resistor?
Determine the current in each case. (a) V = 5 V, R = 1.0 Ω(b) V = 15 V, R = 10 Ω(c) V = 50 V, R = 100 Ω (d) V = 30 V, R = 15 k Ω(e) V = 250 V, R = 4.7 M Ω
Determine the current in each case. (a) V = 9 V, R = 2.7 k Ω(b) V = 5.5 V, R = 10 k Ω(c) V = 40 V, R = 68 k Ω(d) V = 1 kV, R = 2 k Ω(e) V = 66 kV, R = 10 M Ω
Calculate the voltage for each value of I and R. (a) I = 2 A, R = 18 Ω (b) I = 5 A, R = 47 Ω(c) I = 2.5 A, R = 620 Ω (d) I = 0.6 A, R = 47 Ω(e) I = 0.1 A, R = 470 Ω
Calculate the voltage for each value of I and R. (a) I = 1 mA, R = 10 Ω (b) I = 50 mA, R = 33 Ω(c) I = 3 A, R = 4.7 k Ω(d) I = 1.6 mA, R = 2.2 k Ω (e) I = 250 μA, R = 1.0 k Ω(f)
Assign a voltage value to each source in the circuits of Figure 3–30 to obtain the indicated amounts of current. Vs (a) 27 www 3 mA FIGURE 3-30 Vs (b) 100 www 5 A + Vs (c) + 47 02 ww 2.5 A
Calculate the resistance for each value of V and I. (a) V 10 V, I = 2 A = (c) V = 50 V, I = 5 A (e) V = 150 V, I = 0.5 A (b) V = 90 V, I = 45 A (d) V = 5.5 V, I = 10 A
A 20 mΩ current-sensing resistor has 3 A. What is the voltage across the current-sensing resistor?
Calculate R for each set of V and I values. (a) V = 10 kV, I = 5 A (c) V = 500 V, I = 250 mA (e) V = 1 kV, I = 1 mA (b) V = 7V, I = 2 mA (d) V = 50 V, I = 500 μA
Six volts are applied across a resistor. A current of 2 mA is measured. What is the value of the resistor?
A flashlight is operated from 3.2 V and has a resistance of 3.9 Ω when the filament is hot. What current is supplied by the batteries?
The flashlight in Problem 18 uses 26 J in 10 s. What is the power in watts? Data in Problem 18.A flashlight is operated from 3.2 V and has a resistance of 3.9 Ω when the filament is hot.
Convert the following to milliwatts:(a) 1 W (b) 0.4 W (c) 0.002 W (d) 0.0125 W
What is the power in watts when 7500 J of energy are used in 5 h?
Convert the following to megawatts: (a) 1,000,000 W (b) 3 × 106 W (c) 15 × 107 W (d) 8700 kW
What is the power when energy is used at the rate of 350 J/s?
Convert the following to kilowatts: (a) 1000 W (b) 3750 W (c) 160 W (d) 50,000 W
Convert the following to microwatts: (a) 2 W (b) 0.0005 W (c) 0.25 mW (d) 0.00667 mW
Prove that the unit for power (the watt) is equivalent to 1 V × 1 A.
Convert the following to watts:(a) 1.5 kW (b) 0.5 MW (c) 350 mW (d) 9000 μW
What is the power when there are 500 mA of current through a 4.7 kΩ resistor?
Show that there are 3.6 × 106 joules in a kilowatt-hour.
An electric heater works on 115 V and draws 3 A of current. How much power does it use?
If a resistor has 5.5 V across it and 3 mA through it, what is the power dissipation?
A 25 mΩ current-sensing resistor has 5 A of current. What power is dissipated?
If there are 60 V across a 620 Ω resistor, what is the power dissipation?
Convert 6700 watts used for 1 second to kWh.
If a resistor is to carry 2 A of current and handle 100 W of power, how many ohms must it be? Assume that the voltage can be adjusted to any required value.
Convert 5 × 106 watts used for 1 minute to kWh.
Assume that an alkaline D-cell battery can maintain an average voltage of 1.25 V for 90 h in a 10 Ω load before becoming unusable. What average power is delivered to the load during the life of the
How many kilowatt-hours do 50 W used for 12 h equal?
For each circuit in Figure 3–32, assign the proper polarity for the voltage across the resistor.Data in Figure 3–32, Vs (a) + FIGURE 3-32 W R Vs (b) - + w R (c) R w + Vs
A certain type of power resistor comes in the following ratings: 3 W, 5 W, 8 W, 12 W, 20 W. Your particular application requires a resistor that can handle approximately 8 W. Which rating would you
A 50 Ω load dissipates 1 W of power. What is the output voltage of the power supply?
A battery can provide an average of 1.5 A of current for 24 h. What is its ampere-hour rating?
In the light circuit of Figure 3–33, identify the faulty bulb based on the series of ohmmeter readings shown.Data in Figure 3–33. Infinite resistance reading The voltage is disconnected. FIGURE
How much average current can be drawn from an 80 Ah battery for 10 h?
If a battery is rated at 650 mAh, how much average current will it provide for 48 h?
The filament of a light bulb in the circuit of Figure 3–34 (a) has a certain amount of resistance, represented by an equivalent resistance in Figure 3–34 (b). If the bulb operates with 120 V and
If the input power is 500 mW and the output power is 400 mW, what is the power loss? What is the effi ciency of this power supply?
A variable voltage source is connected to the circuit of Figure 3–35. Start at 0 V and increase the voltage in 10 V steps up to 100 V. Determine the current at each voltage value, and plot a graph
Figure 3–36 is a graph of current versus voltage for three resistance values. Determine R1, R2, and R3.Data in Figure 3–36. I (A) 6 5 4 3 2 1 2 FIGURE 3-36 R 3 4 5 R 6 R3 V (V)
A certain electrical device has an unknown resistance. You have available a 12 V battery and an ammeter. How would you determine the value of the unknown resistance? Draw the necessary circuit
If you wish to increase the amount of current in a resistor from 100 mA to 150 mA by changing the 20 V source, by how many volts should you change the source? To what new value should you set it?
If a 300 W bulb is allowed to burn continuously for 30 days, how many kilowatt-hours of energy does it use?
At the end of a 31-day period, your utility bill shows that you have used 1500 kWh. What is the average daily power?
A certain type of power resistor comes in the following ratings: 3 W, 5 W, 8 W, 12 W, 20 W. Your particular application requires a resistor that can handle approximately 10 W. Which rating would you
A 12 V source is connected across a 10 Ω resistor for 2 min. (a) What is the power dissipation? (b) How much energy is used? (c) If the resistor remains connected for an additional
Develop a complete materials list for the load test box in Figure 3–21.Data in Figure 3–21. (()) 0 Load resistor substitution box 100 92 (10 V supply) 1692 (8 V supply) 5.092 (5 V
A 30 mΩ current-sensing resistor is rated for ½ W. What is the maximum current it can have before the rating is exceeded?
What happens to the power dissipated in a resistor if the current is doubled?
Draw the schematic for the load test box in Figure 3–21.Data in Figure 3–21. O Load resistor substitution box 100 92 (10 V supply) 16 22 (8 V supply). 5.092 (5 V supply) - Load 150 (15 V supply)
Determine the current in each of the following cases:(a) 75 C in 1 s (b) 10 C in 0.5 s (c) 5 C in 2 s.
How many coulombs of charge do 50 × 1031 electrons possess?
How many electrons does it take to make 80 μC of charge?
What is the charge in coulombs of the nucleus of a copper atom?
What is the charge in coulombs of the nucleus of a chlorine atom?
Determine the voltage in each of the following cases: (a) 10 J/C (b) 5 J/2 C (c) 100 J/25 C
Five hundred joules of energy are used to move 100 C of charge through a resistor. What is the voltage across the resistor?
What is the voltage of a battery that uses 800 J of energy to move 40 C of charge through a resistor?
How much energy does a 12 V battery in your car use to move 2.5 C through the electrical circuit?
Assume that a solar battery charger delivers 2.5 J of energy when 0.2 C of charge has been moved. What is the voltage?
If the solar cell in Problem 9 has moved the charge in 10 s, what is the current? Data in Problem 9.Assume that a solar battery charger delivers 2.5 J of energy when 0.2 C of charge has been
Six-tenths coulomb passes a point in 3 s. What is the current in amperes?
Figure 2–62 (a) shows color-coded resistors. Determine the resistance value and the tolerance of each.Data in Figure 2–62 (a) A (a) B - C
How many coulombs pass a point in 0.1 s when the current is 1.5 A?
Determine the resistance value and tolerance for each resistor in Figure 2–63. (a) CIT FIGURE 2-63 -GLD (b) (c) CII
Determine the resistance and tolerance of each of the following 4-band resistors: (a) Brown, black, black, gold.(b) Green, brown, green, silver. (c) Blue, gray, black, gold.
Determine the color bands for each of the following 4-band resistors. Assume each has a 5% tolerance. (a) 0.47Ω (b) 270 kΩ(c) 5.1 MΩ
Determine the resistance and tolerance of each of the following 5-band resistors:(a) Red, gray, violet, red, brown (b) Blue, black, yellow, gold, brown (c) White, orange, brown, brown,
Determine the color bands for each of the following 5-band resistors. Assume each has a 1% tolerance. (a) 14.7 k Ω (b) 39.2 Ω (c) 9.76 k Ω
Show the placement of an ammeter and a voltmeter to measure the current and the source voltage in Figure 2–64. Data in Figure 2–64 Vs = FIGURE 2-64 www R₁ R₂
Determine the resistance values represented by the following labels: (a) 220 (b) 472 (c) 823 (d) 3K3 (e) 560 (f) 10M
Show how you would measure the resistance of R2 in Figure 2–64 .Data in Figure 2–64. Vs +14 FIGURE 2-64 W R R
The adjustable contact of a linear potentiometer is set at the mechanical center of its adjustment. If the total resistance is 1000 Ω, what is the resistance between each end terminal and the
In Figure 2–65 what does each voltmeter indicate when the switch (SW) is in position 1? In position 2? Data in Figure 2–65 Vs + SW 92 FIGURE 2-65 + R₁ V1 R₂ + V2
In Figure 2–65, show how to connect an ammeter to measure the current from the voltage source regardless of the switch (SW) position.Data in Figure 2–65. Vs + FIGURE 2-65 SW 2 R₁ + V1 + R₂

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