9780199339136, Chapter 1, Problem 2P

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Chapter 1, Problem 2P Step-by-step solution Step of 7 (a) Value of resistance kΩ Current flowing through kΩ resistor IS 20 mA Power dissipated in the resistor is I²R R = Power dissipated in 1 kΩ resistor 0.4 W For safe operation standard component having power rating greater than 0.4 W should be selected and hence 1/2 power rating components are used. Step of 7 (b) Value of resistance Ris kΩ Current flowing through kΩ resistor is 40 mA Power dissipated in the resistor is I²R = Power dissipated in 1 kΩ resistor is 1.6 W For safe operation standard component having power rating greater than 1.6 W should be selected and hence 2 W power rating components are used Step of (c) Value of resistance Ris 100 kΩ Current flowing through 100 kΩ resistor is mA Power dissipated in the resistor is I²R Power dissipated in 100 kΩ resistor is 0.1 W For safe operation standard component having power rating greater than 0.1 W should be selected and hence 1/8 W or 1/4 W or 1/2 W or 2 W power rating components are used Step of (d) Value of resistance 10 kΩ Current flowing through 10 kΩ resistor is 4 mA Power dissipated in the resistor is I²R = - =0.16 W Power dissipated in 10 kΩ resistor is 0.16 W For safe operation standard component having power rating greater than 0.16 W should be selected and hence 1/4 W or 1/2 W or 1 2 W power rating components are used Step of 7 (e) Value of resistance kΩ Voltage drop across the resistance is 20 V V² Power (P) dissipated in the resistor is R V² P R I = 0.4 W Power (P) dissipated in 1 kΩ resistor is 0.4 W For safe operation standard component having power rating greater than 0.4 W should be selected and hence 1/2 W or 2 W power rating components are used Step of 7 (f) Value of resistance R kΩ Voltage drop across the resistance is 11 V Power dissipated in the resistor is V² R V² R =0.121 W Step of 7 Power dissipated in 1 kΩ resistor IS 0.121 W For safe operation standard component having power rating greater than 0.121 W should be selected and hence 1/8 W or 1/4 W or 1/2 W or 1 2 W power rating components are used