Voltage is the difference in electric potential between two points in a circuit. It is the driving force that causes electrons to move, creating an electric current. So, Voltage drop signifies the decrease in energy provided by a voltage source when electric current flows through circuit components that do not produce voltage. Because the supply energy is wasted, the voltage drop across conductors, connectors, and internal resistances of the source is undesirable. In simple words, the voltage drop is the amount of voltage loss that happens through all or part of a circuit because impedance is known as the voltage drop.
Here in the circuit, the battery (V) is the voltage or power source, V1 is the voltage drop across R1, V2 is the voltage drop across R2 and V3 is the voltage drop across R3.
How to Calculate Voltage Drop?
The Voltage drop formula can be calculated by using the formula below:
V = I×Z
Where,
I = the Current which is measured in Ampere,
Z = Impedance which is measured in ohms.
Voltage drop is measured in Volts ( V)
Sample Problems
Problem 1: A current of 5A is flowing through a closed circuit that has a resistance of 20 Ω. Compute the Voltage Drop across the circuit.
Answer:
Given: Here, we have
- Current (I) = 5A,
- Impedance (Z) = 20 Ω
Thus according to the Voltage Drop formula,
V = I×Z
Substituting the values of Current (I) and Impedance (Z) in the Voltage drop formula,
V = 5 × 20
V = 100 V
Thus voltage drop is 100V
Problem 2: In a closed circuit, there is a resistor of 50 Ω and a current of 2A. Find the Voltage drop if the current is doubled.
Answer:
Given: Here, we have
I = 2 A
According to the condition, Current is doubled
Thus according to the Voltage drop formula
V = I × Z
V = 4 × 50
V = 200 V
Thus voltage drop is 200V
Problem 3: In a closed circuit, the voltage drop is found to be 100 V and there was a resistance of 20 Ω. Find the current flowing through the circuit at that instance.
Answer:
Given: Here, we have
- Voltage drop = 100 v
- Z = 20 Ω
Thus rearranging the formula for Voltage drop,
I = V / Z
Substituting the value of Voltage drop and Impedance,
I = 100 v / 20 Ω
I = 5 A
Thus the current flowing from the circuit is 5 Ampere.
Problem 4: In a closed circuit, the voltage drop is found to be 150 V and there was a current of 7 A. Find the Impedance.
Answer:
Given: Here, we have
- Voltage drop = 150 v
- I = 7 A
Thus rearranging the formula for Voltage drop,
Z = V / I
Substituting the value of Voltage drop and current
Z = 150 / 7
Z = 21.43 Ω
Thus the impudence offered was 21.43 Ω
Problem 5: In a closed circuit with two resistors R1 and R2 in series with values as 15 Ω and 5 Ω respectively and current are 6 A. Find the voltage drop across the circuit.
Answer:
Given: Here, we have
The total resistance in the circuit is R1 + R2 = (15 + 5) Ω = 20Ω
Thus according to the Voltage drop formula,
V = I × Z
V = 6 × 20
V = 120 V
Thus the voltage drop is 120 V.
Problem 6: In a closed circuit with two resistors R1 and R2 in series with values as 10 Ω and 2 Ω respectively and Voltage drop of 80 V. Find the current across the circuit.
Answer:
Given: Here, we have
The total resistance in the circuit is R1 + R2 = (10 +2) Ω = 12Ω
Thus rearranging the formula for Voltage drop,
I = V / Z
Substituting the value of Voltage drop and Impedance,
I = 80 / 12
I = 6.67 A
Thus the current flowing from the circuit is 6.6667 Ampere.
Problem 7: In a closed circuit with two resistors R1 and R2 in parallel with values as 8 Ω and 5 Ω respectively and current is 4A. Find the voltage drop across the circuit.
Answer:
Given:
- Resistor values: R1=8 Ω, R2=5Ω
- Current: I=4 A
For resistors in parallel, the total resistance Rt is given by:
1/ Rt1=1/R1+1/R2
1/ Rt1=1/8+1/5
So, the total resistance is:
Rt=40/ 13 ≈3.08Ω
Now, using Ohm’s Law V=I×R
V=4A×3.08Ω=12.32V
The voltage drop across the circuit is 12.32 V