Question

For the circuit shown below with ideal diodes, the output will be

• A. ( V_{\text{out}} = V_{\text{in}} \) for \( V_{\text{in}}>0 \)
• B. ( V_{\text{out}} = V_{\text{in}} \) for \( V_{\text{in}}<0 \)
• C. ( V_{\text{out}} = -V_{\text{in}} \) for \( V_{\text{in}}>0 \)
• D. ( V_{\text{out}} = -V_{\text{in}} \) for \( V_{\text{in}}<0 \)

Hint:

In a diode bridge circuit, the output voltage follows the input voltage when the input is positive, and the diodes are oriented to allow current flow in the proper direction.

Answer 1

The Correct Option is A

Step 1: Analyzing the circuit.
This is a diode bridge circuit where two diodes (D1 and D2) conduct depending on the polarity of the input voltage \( V_{\text{in}} \). When the input voltage \( V_{\text{in}} \) is positive, diode D1 will be forward biased and conduct, while diode D2 will be reverse biased and not conduct. As a result, the output voltage \( V_{\text{out}} \) will be the same as the input voltage \( V_{\text{in}} \).
Step 2: Behavior when \( V_{\text{in}}>0 \).
When \( V_{\text{in}}>0 \), the current flows through D1, and the output voltage \( V_{\text{out}} \) will be equal to the input voltage \( V_{\text{in}} \).
Step 3: Behavior when \( V_{\text{in}}<0 \).
When \( V_{\text{in}}<0 \), diode D2 will be forward biased and conduct, while D1 will be reverse biased and not conduct. In this case, the output voltage \( V_{\text{out}} \) will again be equal to \( V_{\text{in}} \), but with the opposite polarity (i.e., negative). However, this option is not applicable as per the given choices.
Step 4: Conclusion.
The correct answer is (A), as the output is equal to the input voltage when \( V_{\text{in}}>0 \).