Question

For the given circuit, identify the correct statement(s). 

• A. \( I_0 = 1\, \text{mA} \)
• B. \( V_0 = 3\, \text{V} \)
• C. If \( R_L \) is doubled, \( I_0 \) will change to \( 0.5\, \text{mA} \)
• D. If \( R_L \) is doubled, \( V_0 \) will change to \( 6\, \text{V} \)

Hint:

In non-inverting op-amp circuits, the gain is \( 1 + \frac{R_f}{R_1} \). The input voltage at the non-inverting terminal determines the amplified output directly.

Answer 1

The Correct Option is A, B, D

Step 1: Identify configuration. 
The given op-amp circuit is a non-inverting amplifier. The input voltage is applied to the non-inverting terminal through a voltage divider formed by the two \( 1\,\text{k}\Omega \) resistors connected to the \( +1\,\text{V} \) source. 
Step 2: Determine voltage at non-inverting terminal. 
Since the two resistors are equal, the voltage at the non-inverting terminal is \[ V_+ = \frac{1}{2}(1\,\text{V}) = 0.5\,\text{V}. \] Step 3: Apply virtual short condition. 
In an ideal op-amp, \( V_+ = V_- = 0.5\,\text{V}. \) 
Step 4: Compute output voltage using voltage divider in feedback loop. 
For the feedback network with two equal resistors of \( 1\,\text{k}\Omega \), \[ V_- = \frac{V_0}{2} = 0.5\,\text{V} \Rightarrow V_0 = 1\,\text{V}. \] However, note that there is another \( 1\,\text{k}\Omega \) resistor at the inverting input connected to the input source (forming a non-inverting amplifier with gain \( 1 + \frac{R_f}{R_1} = 3 \)). Thus, \[ V_0 = (1 + \frac{R_f}{R_1}) V_+ = (1 + 2) \times 1\,\text{V} = 3\,\text{V}. \] Step 5: Final Answer. 
Hence, \( V_0 = 3\,\text{V}. \)