Question

What is the Thevenin equivalent voltage across a load in an open-circuited network?

• A. Short-circuit current
• B. Open-circuit voltage
• C. Load voltage
• D. Internal resistance

Hint:

$V_{th}$ = Open-circuit voltage across terminals.

Answer 1

The Correct Option is B

Concept: Thevenin’s Theorem states that any linear electrical network can be replaced by an equivalent circuit consisting of a single voltage source (Thevenin voltage) in series with a resistance (Thevenin resistance).
Step 1: Understanding Thevenin voltage.
The Thevenin equivalent voltage ($V_{th}$) is defined as the voltage measured across the output terminals when no load is connected.
Step 2: Open-circuit condition.
When the circuit is open (no load connected), no current flows, and the voltage across the terminals is called the open-circuit voltage.
Step 3: Relation to Thevenin voltage.
\[ V_{th} = V_{\text{open-circuit}} \]
Step 4: Eliminating other options.

• Short-circuit current: Used to find Norton equivalent
• Load voltage: Depends on load, not open circuit
• Internal resistance: Refers to $R_{th}$

Step 5: Conclusion.
Thus, Thevenin equivalent voltage is the open-circuit voltage.