Question

Operational amplifiers have an intrinsic gain (sometimes called the open loop gain), which refers to the "multiplier" in the amplification of the inputs to produce the output.

Which of the following statements is generally true for operational amplifiers, and indicates the approximation for an ideal op-amp?

	a.	Intrinsic gain is a very large number, and in the ideal case approaches an infinite value.
	b.	Intrinsic gain is a very small number, and in the ideal case approaches zero.
	c.	Intrinsic gain depends on the feedback resistor(s), and in the ideal case is the reciprocal of the resistor value.
	d.	Intrinsic gain is close to one, and in the ideal case is exactly one.

Answer 1

An operational amplifier is a device to amplify the input signal. The open loop gain of an op-amp is the ratio of it's output voltage to the input voltage (which is the difference of volages applied to the inverting and non inverting terminals), when no feedback is applied from input of the op-amp to the output. Typically it's value is very large in the range from 20000 to 200000. In ideal case this open loop gain can be approximately taken to be infinite. So, option (a).