Kirchhoff’s voltage law, States that the sum of all-around any closed loop in a circuit must equal zero.
THE kirchhoff’s voltage law(KVL) CIRCUIT:
The principle known as Kirchhoff’s Voltage Law in 1847 by Gustav R. Kirchhoff, a German physicist, can be stated as such:
“The algebraic sum of all voltages in a loop must equal to be zero”
This is as a result of a circuit loop may be a closed conducting path, thus no energy is lost.
Mathematically, ΣV = 0.
Kirchhoff’s Voltage Law Example, No1:
Three resistors of values: 20 ohms, 30 ohms, and 40 ohms, respectively are connected in series across a 24-volt battery supply. Calculate: a) total resistance, b) circuit current, c) current through each resistor, d) voltage drop across each resistor, e) verify that Kirchhoff’s voltage law, KVL holds true.
a) Total Resistance (RT):
RT = R1 + R2 + R3 = 20Ω + 30Ω + 40Ω = 90Ω
Then the total circuit resistance RT is equal to 90Ω.
b) Circuit Current (I):
Thus the total circuit current is equal to 0.26 amperes.
c) Current Through Each Resistor:
The resistors are wired together in series, they are all part of the same loop and therefore each experience the same amount of current. Thus:
IR1 = IR2 = IR3 = ISERIES = 0.26 amperes
d) Voltage Drop Across Each Resistor:
VR1 = I x R1 = 0.267 x 20 = 5.34 volts
VR2 = I x R2 = 0.267 x 30 = 8.01 volts
VR3 = I x R3 = 0.267 x 40 = 10.68 volts
e) Verify Kirchhoff’s Voltage Law:
Thus (kvl) holds true as the individual voltage drops around the closed loop add up to the total.