Electronics Engineering (ELEX) Board Practice Exam

By configuring the external circuit components of an op-amp, it can function as:

1. A low-pass filter

2. A voltage follower

3. A summing amplifier

4. All of the choices

The correct answer is: All of the choices

An operational amplifier (op-amp) is an incredibly versatile component in electronics, and by configuring the external circuit components, it can take on various functions, including those mentioned in the choices. A low-pass filter allows signals with a frequency lower than a certain cutoff frequency to pass while attenuating signals with frequencies higher than this threshold. By using feedback and specific resistor and capacitor arrangements around the op-amp, it can be made to perform this function effectively. A voltage follower, also known as a unity gain amplifier, is designed to output the same voltage as its input, providing high input impedance and low output impedance. This configuration is straightforward: by connecting the output directly to the inverting input and applying the input signal to the non-inverting input, the op-amp can function as a voltage follower. A summing amplifier takes multiple input signals and effectively "sums" them to produce a single output voltage that is proportional to the weighted sum of the inputs. This is achieved by configuring resistors in a specific manner to allow the op-amp to combine voltages from multiple sources. Since each of these configurations showcases the flexibility and functionality of op-amps, the correct understanding is that the op-amp can be designed to operate as all