What is the input resistance of a differential amplifier?

Simple question (back to basics): For a classical diff. amplifier (Q1 and Q2, finite dynamic resistance re in the common emitter leg): How do we calculate the input resistance at the base of Q1 ?

02 March 2019 4,387 35 View

Who knows this characteristic of the "Butterworth" approach?

By chance, I discovered an interesting property of the "Butterworth" approximation: The product of the quality factors Qp for each pole is constant. This applies to any filter order n. * Even n:...

02 March 2019 9,530 10 View

Where are the limitations of idealized opamp models?

Are there opamp-based circuits which, normally, are designed assuming idealized opamp parameters - however, when simulated based on idealized opamp models (VCVS) they do not function at all?

08 September 2017 1,188 7 View

What are the restrictions for using describing functions in oscillator design?

I am aware that linear oscillators must contain a non-linear part to limit loop gain (or amplitudes) after the start-up phase. Simple case: Amplitude clipping due to supply rails. Then, using the...

06 July 2013 7,396 12 View

error in running a model in Abaqus

Excessive rotation of nodes in node set ErrNodeExcessRotation-Step1

17 August 2021 0 0 View

error in modelling model in Abaqus

Excessive rotation of nodes in node set ErrNodeExcessRotation-Step1

17 August 2021 0 0 View

MGL tools

20 June 2021 0 0 View

what is the simplest definition of ion exchange capacity

What this unit identifies for the ion exchange capacity ca. 0.92 meq. g-1. I am a newcomer in the membrane area. I just started. I highly appreciate your help

08 May 2021 0 0 View

what is the simplest definition of ion exchange capacity

What this unit identifies for the ion exchange capacity ca. 0.92 meq. g-1. I am a newcomer in the membrane area. I just started. I highly appreciate your help

08 May 2021 0 0 View

i have some problem with chtMultiRegionSimpleFoam

--> FOAM FATAL ERROR: Maximum number of iterations exceeded From function Foam::scalar Foam::species::thermo::T(Foam::scalar, Foam::scalar, Foam::scalar, Foam::scalar (Foam::species::thermo::*)(Foam::scalar, Foam::scalar) const, Foam::scalar (Foam::species::thermo::*)(Foam::scalar, Foam::scalar) const, Foam::scalar (Foam::species::thermo::*)(Foam::scalar) const) const [with Thermo = Foam::hConstThermo >; Type = Foam::sensibleEnthalpy; Foam::scalar = double; Foam::species::thermo = Foam::species::thermo >, Foam::sensibleEnthalpy>] in file /home/ubuntu/OpenFOAM/OpenFOAM-4.1/src/thermophysicalModels/specie/lnInclude/thermoI.H at line 66. FOAM aborting #0 Foam::error::printStack(Foam::Ostream&) at ??:? #1 Foam::error::abort() at ??:? #2 Foam::heRhoThermo >, Foam::sensibleEnthalpy> > > >::calculate() at ??:? #3 Foam::heRhoThermo >, Foam::sensibleEnthalpy> > > >::correct() at ??:? #4 ? at ??:? #5 __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6" #6 ? at ??:?

24 March 2021 0 0 View

Can we classify HV and LV lines based on line length?

I have dataset which shows the length of power lines. I need to classify the lines based on the line length. Is there a rule to classify the High voltage (HV) and low voltage (LV) lines based on...

03 March 2021 4,116 4 View

Anyone plz suggest relevant topic for research in image processing+Deep learning.?

I have selected brain tumor images ...but now found that already lots of research done n this topic.

03 March 2021 5,774 3 View

How to increase a model accuracy ?

dear community, my model is based feature extraction from non stationary signals using discrete Wavelet Transform and then using statistical features then machine learning classifiers in order to...

03 March 2021 6,994 5 View

What is the production process of CaFe ferroalloys?

I looking for ferro calcium production process

03 March 2021 1,755 4 View