Question:

In the given op-amp circuit, the non-inverting terminal is grounded. The input voltage is 2 V applied through 1 k$\Omega$. The feedback resistor is 1 k$\Omega$. The output is connected to a 2 k$\Omega$ load to ground and also through a 2 k$\Omega$ resistor to the op-amp output. Find the output voltage $V_0$ and currents $I_1$, $I_0$, and $I_x$. 
 

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In an inverting amplifier, first find $V_0$ using gain formula. Then apply KCL at the output node to compute additional load currents.
Updated On: Feb 15, 2026
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Correct Answer: 3

Solution and Explanation

Step 1: Identify configuration.
Since the non-inverting terminal is grounded, the circuit is an inverting amplifier.
Using virtual ground concept:
\[ V_- = V_+ = 0. \]
Step 2: Calculate input current.
Input resistor = 1 k$\Omega$, input voltage = 2 V.
Voltage at inverting node = 0 V.
Thus,
\[ I_{in} = \frac{2 - 0}{1k} = 2\,\text{mA}. \]
Step 3: Apply KCL at inverting node.
Since op-amp input current is zero, entire 2 mA flows through feedback resistor (1 k$\Omega$).
Thus,
\[ I_1 = 2\,\text{mA}. \]
Step 4: Find output voltage.
Voltage drop across feedback resistor:
\[ V = (2\,\text{mA})(1k) = 2\,\text{V}. \] Since current flows from virtual ground toward output, output must be negative:
\[ V_0 = -2\,\text{V}. \]
Step 5: Current through load resistor (2 k$\Omega$ to ground).
\[ I_0 = \frac{V_0}{2k} = \frac{-2}{2k} = -1\,\text{mA}. \] Magnitude is 1 mA (flowing upward toward node).
Step 6: Current through 2 k$\Omega$ series resistor from op-amp output.
Voltage across this resistor is difference between internal op-amp output and $V_0$.
To maintain $V_0 = -2V$, internal node must supply both feedback current (2 mA) and load current (1 mA).
Thus total current:
\[ I_x = 2\,\text{mA} + 1\,\text{mA} = 3\,\text{mA}. \]
Final Results:
\[ V_0 = -2\,\text{V} \] \[ I_1 = 2\,\text{mA} \] \[ I_0 = 1\,\text{mA} \] \[ I_x = 3\,\text{mA} \]
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