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Parallel Circuits
In a parallel circuit, branches share the same p.d., current divides at junctions, and equivalent resistance is found using reciprocal addition.
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Parallel Circuits
Parallel circuits give electricity more than one path.
The voltage across each branch is the same, but current can split between branches.
Recommended for Class 10
Parallel Circuits
A parallel circuit contains two or more conducting branches connected between the same pair of points.
Charge can therefore travel through different paths.
Potential Difference
The potential difference across each parallel branch is the same:
**V = V₁ = V₂ = V₃**
Current
At a junction, current divides among the branches.
The total current is:
**Iₜ = I₁ + I₂ + I₃**
The currents recombine when the branches join again.
Resistance
For resistors in parallel:
**1Rₜ = 1R₁ + 1R₂ + 1R₃ + ...**
The equivalent resistance of a parallel combination is less than the smallest individual branch resistance.
Example
Two resistors, 6 Ω and 3 Ω, are in parallel.
`1Rₜ = 16 + 13`
`1Rₜ = 16 + 26 = 36`
`1Rₜ = 12`
**Rₜ = 2 Ω**
Why Parallel Connections Are Useful
Different branches can operate independently.
If one branch opens, other complete branches may continue operating.
This is one reason household appliances are connected in parallel rather than as one long series chain.
Parallel Circuits — Advanced
Kirchhoff's current principle gives conservation of charge at junctions:
**ΣIin = ΣIout**
For parallel resistors, conductances add, producing an equivalent resistance below the smallest individual branch resistance.
Common Mistakes
Common Mistakes
- Mistake
Mistake: Current is necessarily the same in every parallel branch. Correction: Current is not necessarily the same in every parallel branch.
- Mistake
Mistake: Voltage is divided across parallel branches. Correction: Voltage is the quantity that is the same across branches connected to the same two points.
Revision Zone
60-Second Revision
Quick cues from this topic — use them for last-minute revision.
Parallel → multiple paths.
Voltage → same.
Current → divides.
Total current → branch currents add.
- Definition
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Practice
PQ
Q1. Define parallel circuit.
PQ
Q2. State voltage rule.
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Q3. State current rule.
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Q4. Find equivalent R of two 4 Ω resistors.
PQ
Q5. Explain independent branches.
Exam Practice
EQ
Q1. Compare series and parallel circuits.
EQ
Q2. State junction current rule.
EQ
Q3. Explain voltage across parallel branches.
EQ
Q4. Solve parallel resistance numerical.
EQ
Q5. Explain why homes use parallel circuits.
School-standard facts for Matric and Intermediate. Original explanations — not copied from textbooks.