Question

Write short note input bias current of operational amplifier

Answer 1

In an operational amplifier, the input bias current is a small amount of current flowing inside or outside the inputs.

• It influences the inputs by applying an offset voltage equal to the resistance of the circuit input times the bias current. Having input impedance low decrease input bias voltage errors for this purpose.
• Though it does pass inside and outside, ideally it is zero.
• It is a bi-polar junction transistor circuit, allowing a small current to be continuously fed into the transistor to conduct current in the linear portion.