A couple of definitions...

[jrmintz]

Hi all,

There are a few things I think I sort of understand but I'd like to really understand. Well, there's a lot actually, but these are the ones I can remember:

What are comparators and integrators, and how are they different from opamps?

What is hysteresis?

Thanks!

:guinness: :sam:

 

[NewYorkDave]

A comparator is essentially a saturated opamp.
http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/opampvar8.html

An integrator is also an op-amp application. The integrator produces a voltage output proportional to the product (multiplication) of the input voltage and time. It produces a steadily changing output voltage for a constant input voltage. A typical application is wave-shaping.

As you can see, comparators and integrators are actually applications of op-amps, although it's true that you can buy chips that are optimized for particular operations. Remember, op-amps--operational amplifiers--were developed to perform analog computing functions such as addition (summing), differentiation, integration and so on.

As for hysteresis:
http://www.lassp.cornell.edu/sethna/hysteresis/WhatIsHysteresis.html
Besides magnetic materials, another good example of hysteresis at work is a neon bulb "relaxation" oscillator, which takes advantage of the neon's hysteresis--the fact that it does not conduct and then cease to conduct at the same voltage threshold.

 

[jrmintz]

Thanks, Dave. I get it. I'm reading a book you mentioned, 'Troubleshooting Analog Circuits' by Robert Pease. It's really excellent - he has a gift for being clear and light at the same time. I'm really learning a lot. For better or worse, the first thing I always learn is that there's another thing I don't know...

:shock: