Activity 1.1.5a Circuit Theory: Hand Calculations Introduction In this activity you will gain experience applying Ohm’s Law and Kirchhoff’s Voltage and Current Laws to solve simple series and parallel circuits. Equipment • Calculator Procedure 1. For each of the resistors shown below, use Ohm’s Law to calculate the unknown quantity. Be sure to put your answer in proper engineering notation and use the correct units. 3.5/470= 7.43 mA 3.5/ 15.5 ua = 225.806kΩ 1.4 mA *22kOhms = 30.8kV 2.4 mV/ 10uA = 240Ω 20V/ 6.8 k ohms = 2.94mV 2.5 A/120 ohms = 300V © 2014 Project Lead The Way, Inc. Digital Electronics Activity 1.1.5a Circuit Theory: Hand Calculations – Page 1 2. For each of the circuits shown below, calculate the value for RT. Be sure to put your answer in proper engineering notation and use the correct units. Calculations: a) 820 + 1200 + 150 = 2.17k ohms a) b) 470 + 3900 + 4700 + 1800 = 10.9k ohms b) c) 1/(1/5600+1/680+1/8200) = 564.49 ohms c) d) 1/(2/600+2/300+ 1/200) = 66.7 ohms d) © 2014 Project Lead The Way, Inc. Digital Electronics Activity 1.1.5a Circuit Theory: Hand Calculations – Page 2 3. Using the laws of circuit theory, solve for RT, IT, VR1, VR2, VR3, & VR4. Be sure to put your answer in proper engineering notation and use the correct units. Using the calculations from problem (3), verify your results using Kirchhoff’s Voltage Law. 2700+10000+3300+8200= 2.42 k ohms 6/2420 = 2.48 uA VR1 = 2700*2.48uA=669.6 uV VR2 = 10000*2.48uA = 2.48mV VR3 = 3300*2.48uA = 818.4uV VR4 = 8200*2.48uA=2.034mV RT*IT=VT 0.00248*2420=1.0016 4. Using the laws of circuit theory, solve for RT, IT, IR1, IR2, & IR3. Be sure to put your answer in proper engineering notation and use the correct units. Using the calculations from problem (4), verify your results using Kirchhoff’s Current Law. 1/(1/8200+1/6800+1/4700) =2.08 k ohms IR1=12/8200=1.46mA IR2=12/6800=1.77mA IR3=12/4700=2.55mA IT = 5.78mA © 2014 Project Lead The Way, Inc. Digital Electronics Activity 1.1.5a Circuit Theory: Hand Calculations – Page 3