Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.
an integrator is an op ampm circuit whose output is proportional to the integral of of the input. if the feedback resistor in an inverting amplifier is replaced by a capacitor we get an integrator.
To be precise, the circuit diagram above is an inverting integrator circuit, which means that there is an additional phase shift of 180 deg in addition to the 90 deg. belonging to the normal integrating function.
However, your question was "How does an integrator works" - and I think you expect an explanation rather than only a circuit, right ?
OK, here are some corresponding answers:
1.) In the gain formula G=-R2/R1 for an inverting amp you can replace resistor R2 by 1/sC. This results in the classical integrator transfer function
H=-1/sT with T=R1*C (integrating constant).
2.) If you calculate in the time domain set iR=iC (see figure above) and set
Uout=1/C( ∫iC*dt ) and iR=Uin/R1. The result is Uout=-1/T( ∫Uin*dt ).
3.) Another explanation is based on the MILLER-Effekt:
A cap is charged via a resistor. But it is the MILLER capacitor which is C multiplied by the opamp gain. Thus, we get an RC-lowpass with a very small corner frequency (below 1 Hz) which works like an integrator above app. 10 Hz.
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.
