Question

Typed please. List an application of an op-amp comparator configuration, the advantages and disadvantages of the op-amp comparator configuration, and why you would use an op-amp comparator rather than another device.

Answer 1

Applications of Op-amp comparator:

i. It is useful in the humidity monitoring system of soil based on wireless sensor networks using Arduino, where comparator will compares moisture level signals with the predefined reference signal. Then it will send a signal to the microcontroller.Based on the signal received from the sensing arrangement and comparator signal, the water pump will be operated.

ii. It is used in heart beat sensor for monitoring human's heart beat rate.

iii.Comparator is also used for triggering the alarm in Smoke Alarm Circuit.

Advantages of the op-amp comparator configuration:

i. The advantage of comparator(i.e.Schmitt trigger circuit) is immune to erratic triggering caused by noise or slowly changing input signals within the hysteresis band producing a cleaner output signal as the op-amp comparators output is only triggered once

ii. High input impedance at the input terminals and low output impedance at the output terminal(s) are particularly useful features of an op-amp.

iii. Op-amps have several benefits over dedicated comparators, costing less and minimizing printed circuit board (PCB) area.

iv. Op-amp comparators are used in Analog-to-digital converters, zero cross detectors and absolute value detectors.

Disadvantages of the op-amp comparator configuration

i. an op-amp typically has a lengthy recovery time from saturation since these are designed to operate in the linear mode with negative feedback. Hence,all op-amps have an internal compensation capacitor which imposes slew rate limitations for high frequency signals. Consequently, an op-amp makes a sloppy comparator with propagation delay increased.

ii. Since op-amps do not have any internal hysteresis, an external hysteresis network is always necessary for slow moving input signals.

iii. A comparator is designed to produce well limited output voltages that easily interface with digital logic. Compatibility with digital logic must be verified while using an op-amp as a comparator.

iv. Some multiple-section op-amps may exhibit extreme channel-channel interaction when used as comparators.

Reson for using an op-amp as comparator rather than other device

i. Other comparators are not immune to the speed-power tradeof.

ii. Like, op-amp confuguration, other devices do not have infinite input resistance.

iii. Unlike op-amp based comparators, other comparotors are costly in nature ans slower.

iv. op-amp based comparators have high immunity to noise whereas other devices do not have this feature.

v. op-amp based comparators occupies less are in PCB when compared to that of other comparators.