What is the expected gain of a unity-gain buffer amplifier?

From the video, the gain expression for the non-inverting amplifier is,

$v_o = v_{in}$

The gain is $1$.

Starting from a blank schematic, design and simulate an unity-gain buffer amplifier with a gain of $1$.

Include a voltage probe on the output port.

Circuit sandbox

Click on TRAN to run a transient simulation.

Does the simulation match your gain calculation?

Add a voltage probe to $v_{in}$ and simulate again.

Notice how the output and input voltages overlap one another.

Change the value of the input voltage and run TRAN again.

Hint: Double-click on the input voltage source to modify its magnitude.

Verify the buffer amplifier does what you expect.

Notice that $v_o$ and $v_{in}$ are the same. When we model an ideal opamp the virtual ground is perfect, $v_o = v_{in}$. In the real world there will be a very slight difference due to the offset voltage of a real opamp. You find the offset voltage listed on the opamp’s data sheet.