DC Circuits
- How does source transformation convert a voltage source into an equivalent current source? In one line A practical voltage source V with series resistance R can be replaced by a current source I = V/R with the same R in parallel, a... 1
- What are Kirchhoff's current law and voltage law, and how do you apply them to a circuit? In one line Kirchhoff's Current Law (KCL) says the total current entering a node equals the total current leaving it, and Kirchhoff's Voltag... 1
- How do star-delta and delta-star transformations simplify resistor networks? In one line Star-delta transformation replaces three resistors connected in a star (Y) with an equivalent set of three in a delta (triangle)... 1
- What is the difference between ideal and practical voltage and current sources? In one line An ideal source gives a fixed voltage (or current) no matter what load is connected, while a practical source has internal resis... 1
- What does the superposition theorem state and how is it used with multiple sources? In one line In a linear circuit with several independent sources, the current or voltage in any element equals the algebraic sum of the valu... 1
- How do you solve a DC circuit using mesh analysis with mesh currents? In one line Mesh analysis assigns a loop current to each window (mesh) of a planar circuit, writes KVL for every mesh, and solves the result... 1
- How does Thevenin's theorem replace a complex network by a single source and resistance? In one line Thevenin's theorem says any linear two-terminal network can be replaced by one voltage source V_th in series with one resistance... 1
- How do you solve a DC circuit using nodal analysis with node voltages? In one line Nodal analysis picks one node as reference (0 V), writes KCL at every other node in terms of unknown node voltages, and solves f... 1
- How does Norton's theorem represent a network as a current source with parallel resistance? In one line Norton's theorem says any linear two-terminal network can be replaced by a current source I_N in parallel with a resistance R_N... 1
- What is the maximum power transfer theorem and what load resistance gives maximum power? In one line A source delivers maximum power to a load when the load resistance equals the Thevenin resistance of the source network, R_L = R... 1
- Using source transformation find the current flowing the 8 Ω resistance [Circuit: a common bottom wire. Left: an 18 V battery (longer plate, +, at the top) from the bottom wire up to the top-left corner. Top wire: top-left corner → resistor (label pr… Reading of the figure: the first series resistor is taken as 6 Ω (its label is over-struck in the print; this is the standard version of the... 1
- Convert the star circuit into its equivalent delta circuit. [Figure: star network with centre N; arm N–A = 2 Ω (A at the top), arm N–B = 4 Ω (B at lower left), arm N–C = 6 Ω (C at lower right).] R_A = 2 Ω, R_B = 4 Ω, R_C = 6 Ω. Sum of products: R_AR_B + R_BR_C + R_CR_A = 2(4) + 4(6) + 6(2) = 8 + 24 + 12 = 44\ Ω² . Star → delta: R_AB... 1
- Using Norton's theorem, calculate the current through 3 Ω resistor across the terminals A and B in the given circuit. [Circuit: Top wire: top-left node T → 8 Ω → top-middle node P → 2 Ω → terminal A. A 3 Ω resistor is connected between A and B (right… Step 1: Norton current I_N — remove the 3 Ω and short A–B. Take node E (= B) as reference; unknowns V_P, V_D. Branch currents leaving P: thr... 1
- Find the current through 4 Ω resistance using Nodal analysis[Circuit: a common bottom wire (reference). Left branch: a 6 V battery (longer plate, +, at the top) in series with a 3 Ω resistor, going up from the bottom wire to the top-left corner; the… Assumption: the direction of the 5 A source is not marked in the figure; it is taken as delivering 5 A upward into node B (the usual form of... 1
- State the condition of maximum power transfer in a circuit and write the expression for maximum power. Condition: a linear DC network delivers maximum power to a load resistance R_L when the load resistance is equal to the Thevenin (internal)... 1
- Find the current through 8 Ω resistance using Thevenin's Theorem. [Circuit diagram: printed as an almost completely black (over-darkened) box in the source scan; element values and connections cannot be read — partly illegible in the source scan.] Note: the circuit for this question is illegible in the source scan, so the numerical answer cannot be computed here. The complete Thevenin... 1
- Find Current through 4 Ω resistance using Nodal analysis[Circuit: a common bottom wire (reference). Left branch: a 6 V battery (longer plate, +, at the top) in series with a 3 Ω resistor, going up from the bottom wire to the top-left corner; the top… Assumption: the direction of the 5 A source is not marked in the figure; it is taken as delivering 5 A upward into node B (the usual form of... 1
- Determine Norton's equivalent circuit which may be used to represent the given network at the terminals AB and hence find current through 5 Ω resistance. [Circuit: a common bottom wire ending at terminal B. Left branch: a 12 V source (circle, + at th… Step 1: Norton current I_N (remove 5 Ω, short A–B). The 4 Ω is then in parallel with 6 Ω across N–B. R_total = 2 + (6∥4) = 2 + 2.4 = 4.4\ Ω... 1
- Using Superposition theorem, find voltage across 4 Ω resistor. [Circuit: a common bottom wire (reference). Left vertical branch: a 10 A current source between the bottom wire and the top-left wire, arrow pointing upward (current delivered into the to… Take the bottom wire as reference (0 V). Let V_X be the voltage of node X = voltage across the 4 Ω resistor. Step 1: 10 A source acting alon... 1
- State and prove the Maximum power transfer theorem. Derive the formula of Maximum power delivered. Statement: A DC network (linear, bilateral) delivers maximum power to a load resistance R_L when R_L equals the Thevenin (internal) resistan... 1
- Find current flowing through 1 Ω resistance by Node analysis. [Circuit: a common bottom wire (reference). Left vertical branch: a 4 V battery from the bottom wire up to the left node L (longer plate, +, at the top). From L the left vertical wire cont… Reference: bottom wire = 0 V. Node voltages: V_L, V_M, V_R. The 4 V source is directly between L and reference ⇒ V_L = 4 V. KCL at node R (c... 1
- Write formulas for Delta to Star and Star to Delta transformation. Let the delta resistances be R₁₂, R₂₃, R₃₁ (between terminals 1-2, 2-3, 3-1) and the equivalent star resistances be R₁, R₂, R₃ (connected fr... 1