Discussion in 'General Electronics Chat' started by fahadatnet, Mar 14, 2005.

  1. fahadatnet

    Thread Starter New Member

    Dec 22, 2004
    Can anybody tell me what is the diffference between op-amp & comparator?

    How the voltage Vid is obtained in case of comparator & not in op-amp?
    Thanks in advance. :)
  2. hgmjr

    Retired Moderator

    Jan 28, 2005
    The opamp and the comparator are very similar devices. They both have a negative input and a positive input. They even share the same schematic symbol representation.

    An opamp can be operated as comparator but a comparator makes a very poor opamp.

    The primary difference is that the comparator, as the name implies, is used to compare the voltage present at each of its input terminals and set it output high or low based on the relationship between the two voltages. The circuitry inside is optimized for this role so the gain of a comparator is typically very high 1,000,000 or more. As a result of this very high gain the comparator ends up with a significant internal delay from its input to its output. This makes it unsuitable for use in as a linear amplifier.

    Ordinarily, one of the inputs is set to a reference voltage and the other input is used to monitor the level of a voltage that changes as a function of some condition such as temperature, speed and the like.

    The opamp on the other hand is optimized for linear operation and so its input to output delay is kept as short as possible and its open-loop gain is set as high as practical without introducing any more delay than possible.

    Take a look at the tutorials on this website and you will find a wealth of information that will help you gain a better understanding of some of the ways that opamps and comparators are used.

    Hope this help a little bit.
  3. onward120

    New Member

    Mar 15, 2005
    :) they are almost same because u can make a comparator using Op-amp