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trond Senior Member Offline Posts: 168 Glasgow, Scotland	what could make an integrator? Aug 07^th, 2005, 1:18am I was wondering what circuits might act as a continuous time integrator? I do not mean obvious circuits like RC Integrators . For example, we all know a VCO can be modelled as 1/s. An integrated accelerometer was pointed out to me as well. I am curious what people have come across. Thanks for any feedback.
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Geoffrey_Coram

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Re: what could make an integrator?
Reply #1 - Aug 22^nd, 2005, 5:32am

If you're integrating something, you need a state variable to keep track of the result, don't you? This means either a capacitor (charge as the state) or an inductor (current as the state). I guess with MEMS you can integrate to get velocity or position. If you are doing microfluidics, you can integrate to get total fluid volume. But if you're really interested in *circuits*, you're pretty much stuck with capacitors and inductors.

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trond

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Glasgow, Scotland

Re: what could make an integrator?
Reply #2 - Aug 22^nd, 2005, 7:57am

Thanks for your feedback.
So far the only other thing I have come accross (which is still a circuit, sort of) is a magnetic sensor. There I suppose a magnetometer senses a magnetic field by means of the current it induces in a coil. A voltage is generated which proportional to the rate of change of the flux.
So emf=-d(phi)/dt, an integrator. Yay.

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jbdavid

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Silicon Valley

Re: what could make an integrator?
Reply #3 - Sep 20^th, 2005, 10:47am

Doesn't EVERY conservative system have an integrator? 8)

Position is integral of velocity..
Velocity is integral of force/mass
--
same with the angular systems..
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In plumbing a resevoir (my RO system has one with an air pressure bladder under my sink.. )

Maybe I should write a verilog-A model of that system?
Cheesy

In Solid-State systems.. The Capacitor has been the fundamental (analog) integrator.. as Inductors are harder to design well in silicon..
with Mems - you could use position and a spring to store
the energy..
Jonathan

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jbdavid
Mixed Signal Design Verification

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