Resistor Network Trick to Find Ammeter Current | JEE Main 2026 PYQ

Question

Find the current through the ammeter (in A) in the given circuit.

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Solution

Step 1: Capacitor at Steady State

In steady state (DC supply), the capacitor behaves as an open circuit.

Therefore, no current flows through the capacitor branch.

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Step 2: Simplify the Right Side Parallel Combination

The two 8 Ω resistors are connected in parallel.

R = (8 × 8)/(8 + 8)

R = 64/16 = 4 Ω

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Step 3: Series Combination

The obtained 4 Ω resistor is in series with the 4 Ω resistor.

R = 4 + 4 = 8 Ω

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Step 4: Parallel Combination

Now the circuit contains two 8 Ω branches in parallel.

R = (8 × 8)/(8 + 8)

R = 64/16 = 4 Ω

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Step 5: Total Resistance

The remaining 6 Ω resistor is in series with the equivalent 4 Ω.

R_total = 6 + 4 = 10 Ω

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Step 6: Total Current

Using Ohm's Law,

I = V/R

I = 10/10 = 1 A

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Step 7: Ammeter Current

The total current of 1 A reaches two identical 8 Ω parallel branches.

Since both branches have equal resistance, the current divides equally.

I_ammeter = 1/2 = 0.5 A

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Final Answer

Current through the ammeter = 0.5 A