Recent content by eyeweyew

It is voltage at a point due to other point charges. I edited my post to clarify it. Thanks!

I reviewed some of the fundamental physics and I looked back at the equation for Electric potential at a point p: $$V(p) = k \sum_{i} {\frac {q_i} {r_i}}$$ where - p is the point at which the potential is evaluated; - ri is the distance between point p and point i at which there is a nonzero...

I think I got it. I mixed up the current i1 going into the input port with the current source i

I spent the whole day trying to figure why transresistance amplifier modelled with z-parameters does not match with nodal analysis results but I sill can't figure out. I desperate need help on this... I write down step by step what I did for a very simple transresistance amplifier here and hope...

The final feedback would be fvo where f=RE/(RE+Rf) so it is from right to left.

Nevermind, the results matched when I include h21.

For a standard non-inverting amplifier as below: With nodal analysis, I got $$\frac {v_o} {v_i}=\frac {R_EZ_o+aZ_iR_E+aZ_iR_f} {R_ER_f + R_EZ_i + R_EZ_o + R_fZ_i + Z_iZ_o + R_EaZ_i}$$ However, with the feedback network of the amplifier converted to a h-parameter network as below: With nodal...

From page 4-9 of this lecture note https://pallen.ece.gatech.edu/Academic/ECE_6412/Spring_2004/L180-PSRR-2UP.pdf, it gives example on how to model a Two-Stage Op Amp to find the PSRR- when VBias is connecting to ground as oppose to when VBias is connecting to Vss. One thing I don't understand is...

Thanks for all the answers! I understand there are gaps between the academic and reality. In academic/mathematical perspective, assume this simple test for negative feedback system deduced from Nyquist criterion for stability is correct(at least in most common cases): And one could proceed...

A few places such as wikipedia mentioned that if loop gain > 1, the system will be unstable. I am not sure if loop gain less than unity imply stable system or not? Reference: https://en.wikipedia.org/wiki/Positive_feedback

Does the following simple test deduced from Nyquist criterion also apply to positive feedback or it needs to be modified? If magnitude of loop gain i.e. |T (jω)| > 1 at the frequency where phase(T (jω))= −180◦, then the amplifier is unstable. Reference: Analysis and Design of Analog...

Ok, Never mind. The derivation is actually on page 332-333 in the same book.

I am trying to figure out how the derivation of equation 6.69 come about on page 426 in the book Analysis and Design of Analog Integrated Circuits, 5th Edition by Gray and Meyer. They defined on page 424 under section 6.3.3 the input offset voltage (VOS) of op amps with differential inputs and...

I think I got it. Thanks!

TL;DR Summary: How to find Time domain equation for RC circuit with AC input from inverse laplace transform For a simple RC circuit with AC input such as this: https://www.electronics-tutorials.ws/wp-content/uploads/2013/08/rc12.gif?fit=310%2C151?fit=310,226. If the AC input is just a simple...