Question

The slew rate of an ideal op amp is
A. Infinite
B. Zero
C. Half of the voltage gain
D. 10 times the voltage gain

Answer 1

Hint: Slew rate is measurement of the response of an operational amplifier. For an ideal operational amplifier, time delay is negligible. Hence it has an infinite slew rate. That means it can provide output voltage simultaneously with the input voltage changes.

Complete step by step answer:
Slew rate is the rate at which the output of an op-amp can change with respect to the input. It is measured as a change in voltage in a given time.
$$\Rightarrow {\displaystyle \frac{\mathrm{\Delta }v}{\mathrm{\Delta }t}}$$
For an ideal op-amp the time delay is zero. Hence according to the equation, the slew rate for an ideal op-amp is infinity. So, the correct option is A.
Additional information: Operational amplifier is a high gain electronic voltage amplifier. It consists of one or more differential amplifiers. Op-amp’s output voltage is proportional to the difference of the two-input voltage. To minimize the loading, we need an ideal op-amp with negligible resistance to the output.

Characteristics of an ideal op-amp;
Infinite open-loop gain: Output voltage would result from an input voltage of virtually zero.
Infinite input impedance
Zero output impedance: To reduce the loss of signal in the amplifier itself.
Infinite common mode rejection ratio: It measures the ability to reject the input signals commonly to both input leads.
Infinite slew rate: It measures the working of an amplifier by checking the response to the change in input signal.
It can provide infinite bandwidth: Same factor can amplify all frequencies.

Note: Ideal op-amp is a condition to minimize the load. Hence it can produce output voltage without any loss. Op-amp’s are used for the DC amplification in signal conditioning.