Ele599I E-Testing II
Mid Term Exam
Question 1 answer

Figure 1

NAME________________________________________

1.

1. What is the effect of a 3 mV input offset voltage on the output of the circuit shown in Figure 1?

   Answer

   The input offset appears at the non-inverting input and is multiplied by the non-inverting gain.

   Vout = Vos[1 + 50/12.5] = 15 mV

2. What is the effect of a 2 uA input bias current on the output of the circuit shown in Figure 1?

   Answer

   Since 1/50 + 1/12.5 = 1/10

   Both opamp inputs see the same resistance, therefore bias current into the minus input cancels the effect of bias current into the opamp plus input.

   The output voltage due to bias currents is zero.