Question

Two p-n junction diodes \(D_1\) and \(D_2\) are connected as shown in the figure. \(A\) and \(B\) are input signals and \(C\) is the output. The given circuit will function as a _______. 

• A. NOR Gate
• B. NAND Gate
• C. AND Gate
• D. OR Gate

Hint:

In diode logic with a pull-up resistor, diodes pulling the output LOW usually implement an AND gate.

Answer 1

The Correct Option is C

Concept: Diode logic circuits use the conducting (forward-biased) and non-conducting (reverse-biased) states of diodes to implement basic logic gates. 
Step 1: Understand the circuit 
A pull-up resistor \(R\) connects the output node \(C\) to \(+5\,\text{V}\). 
Diodes \(D_1\) and \(D_2\) connect inputs \(A\) and \(B\) respectively to the output node. 
The diodes are oriented such that a LOW input can pull the output LOW. 

Step 2: Truth table analysis 

Explanation: 
If either \(A=0\) or \(B=0\), the corresponding diode conducts and pulls \(C\) LOW. 
Only when both \(A=1\) and \(B=1\), both diodes are reverse-biased and the pull-up resistor makes \(C\) HIGH. 
Final Answer: \[ \boxed{\text{AND Gate}} \]