Question

Consider an op-amp circuit shown in the figure below :




Assuming the op - amp to be ideal, then the value of output voltage $V_{out}$ is equal to

Answer 1

Since, the amplifier is an non-inverting amplifier thus,


$V_{out}=(1+\frac{R_2}{R_1})V_1$

$Now,V_t=V_a\times \frac{10k}{15k}-\frac{V_a\times 5k}{15k}$

$V_t=\frac{V_a}{3}$

$V_{out}=(1+\frac{10k}{5k}).V_t=3\times \frac{V_a}{3}=V_a$