Electrical Engineering Principles
Next topic >> Parallel Circuit
What is series circuit?
The series circuit is common circuit which describe every component of load are connected in one straight lines.
Figure 1 Series circuit
Series Circuit Rules and Behavior
Total resistance (in ohm) is added from each individual resistances.
Voltage in each resistance shall be added to get total
Total current remains the same throughout all point near resistance.
Series Formula
Rt = R1 + R2 + R3
Vt = VR1 + VR2 + VR3
It = IR1 = IR2 = IR3
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