4 |   series circuit

Example calculation 

 1)   Given R1=5 Ω , R2=10 Ω and R3=15 Ω, find total resistance (Rt).     

          Apply the formula    Rt = R1 + R2 + R3  

                                                   Rt = 5 + 10 + 15      = 30 Ω

2)   Resistance of R1=10 Ω, R2=20 Ω , R3=35 Ω .  Given the current flow through R1,R2,R3 is 1.2 ampere,  calculate each voltage across all R1, R2, R3 and total voltage (Vt) .

Solution:     

          VR1 = I x R1       = 1.2A x 10 ohm = 12 volt

          VR2 = I x R2       = 1.2A x 20 ohm = 24 volt

          VR3 = I x R3       = 1.2A x 35 ohm  = 42 volt  

          Vt  = VR1 + VR2 + VR3   =  12v + 24v + 42v =  78 volts  (voltage total)

3)  Resistance of R1=6 Ω, R2=18 Ω and voltage total is 50 volt, calculate each current across R1 and R2.   

Solution:      Total resistance, Rt   ;  Rt = R1 + R2      = 6 + 18 = 24 Ω 

                          Total current                 ;  It =  Vt / Rt   = 50v / 24 ohm   =  2.08 A

                           Current flow across R1 and R2 is same ;    2.08 A

                          Voltage across each resistor R1   =   R1 x I   = 6 ohm x 2.08 A = 12.48 volts

                          Voltage across each resistor R2   =   R2 x I   = 18 ohm x 2.0 A = 37.44 volts

                           Voltage total is ,   Vt = VR1 + VR2   =  12.48v + 37.44v  = 49.92 volts