Question

Determine the voltage input to the inverting terminal of an op amp when −40 μV is applied to the non-inverting terminal and the output through an open-loop gain of 150,000 is 15 V.

Answer 1

The voltage input to the inverting terminal is 60μV

Step-by-step explanation:

Given;

open-loop gain, A = 150,000

output voltage, V₀ = 15 V

voltage at the inverting input,
`V_n` = −40 μV = 40 x 10⁻⁶ V

The relationship between output voltage and voltage at the inverting input is given as;

`V_o = A(V_p -V_n)\\\\15 = 150,000(V_p -(-40*10^(-6)))\\\\15 = 150,000 (V_p +40*10^(-6)) \\\\V_p +40*10^(-6) = (15)/(150,000) \\\\V_p + 40*10^(-6) = 1 *10^(-4)\\\\V_p + 40*10^(-6) = 100 *10^(-6)\\\\V_p = 100 *10^(-6) - 40*10^(-6)\\\\V_p = 60 *10^(-6)\\\\V_p = 60 \ \mu V`

Therefore, the voltage input to the inverting terminal is 60μV