Question

uestion # R1 R2 10? 16? S1 V1 10V R4 90? R5 9? 2A R3 2? For the circuit shown in the above figure: a) Calculate the voltage across the switch S1 when the switch is open. Determine which node has higher voltage "d" or "c". Show all the steps of your work. Values without the work steps are ZERO points. b) Calculate the current through the R2 resistor when the switch S1 is closed. Does this current flow from node “b" to "c"? Show all the steps of your work. Values without the work steps are ZERO points. c) Does R2 absorbs the maximum power from the circuit? Explain

Answer 1

From the given circuit a) Switch S_1 is open Current through 16 Ohm is zero , it is open V_C = ? Using voltage division rule V_C = 10 times 90/90 + 10 = 9V V_C = 9V Voltage at 'd' V_d = 2 times 9 = 18 V Apply KVL -V_C + V_S_1 + V_d = 0 V_S_1 = V_C - V_d = 9 - 18 V_S_1 = -9 V Therefore Voltage across switch S_1 is V_S_1 = -9V V_C = 9V , V_d = 18 V 'V_d' is higher voltage implies 'd' is higher voltage (b) When 'S_1' is closed Using Source transformation Apply KCL at node V_y V_y - 10/10 + V_y - 18/16 + 2 + 9 = 0 V_y [1/10 + 1/27] = 10/10 + 18/27 V_y = 12.162 V Current through 'R_2' resistor is