Recent content by fobos3

Is D like a specific operator(differential operator?) or is it any operator?

From Euler's formula: e^{i\gamma} = \cos\gamma + i\sin\gamma If the exponential approaches 1, then gamma approaches 0. Now: \cos 0 = 1 Also, when gamma is small: \sin\gamma \approx \gamma Which you can get from the Taylor series. Finally: e^{i\gamma} \approx 1 + i\gamma I suppose you can...

Actually, I found what I was looking for: Semiconductor Physics and Devices by Donald A. Neamen. Your suggestion also seams interesting but it appears to focus on material properties rather than semiconductor devices. I was looking primary in semiconductor device physics and the book by Neamen...

Hi, I am looking for a good book or any other online resource on semiconductor physics. What I need the book to cover is: The PN junction i.e. the diode BJT transistors MOSFETS In particullar I am interested in the derivation of the equations of the above components, the Shockley...

I was thinking of powering a microcontroller directly from a buck-boost converter, but after doing a few calculations I ran into the following problems: Ringing when switching on/off Current rise time You can get the ringing down with a snubber. The current rise time however is a big...

I don't know where you are located but here in the UK you can get an Altera Cyclone IV FPGA for about £15, which has a maximum clock rate of 472.5MHz. However, there are a few disadvantages when you use an FPGA in your circuit: An FPGA doesn't have an internal oscillator. You need to use an...

I need it to work from 0.05Hz up to about 500MHz Yeah, I thought so. Thanks for your help.

I see what you've done. Indeed, I have tried that and my problem is the offset at the output that is also present in your simulation. Maybe there is no way to remove it and I'll need to add a differential stage. The amplifier needs to be able to work with low frequencies so AC coupling is not...

Vin is a 1mV sine wave with no offset, V is 10V, and the R1 and R2 resistor are in the kOhm range. I change their ratio to set up the gain. The problem I am having is that the output is given by: V_{out} = V_{be}-\frac{R_1}{R_2}(V_{in} - V_{be}) So, if I set the gain to 1 or 2 my sine wave...

circuit

Hi. I am trying to design a common emitter amplifier with a current source as an active load. Currently I am simulating it in SPICE using an ideal current source with an NPN transistor. I have the emitter connected to ground, the input signal is applied at the base and the collector as the...

I am reading through my fluid mechanics book and there is a derivation of Torricelli's theorem i.e. V = \sqrt{2gh}. The author's pick the datum line at the middle of the jet and show that: h = \dfrac{p}{\gamma} + \dfrac{V^2}{2g} where h is the distance from the jet to the surface of the...

Hi I'm looking for a good, in depth book on continuum mechanics and classic gauge theory. Can you suggest something? What I know about the subject is the chapter in Goldstein's classical mechanics.

Yes, just put the Lagrangian equal to the potential energy. However I think you will find that, if you have an equilibrium the potential energy is at minimum more useful. For example consider the cantenary. V=\int_C my\,ds Now if you use Lagrangian mechanics you would be minimising \iint_C...

Yes I see that now. Can you explain where I went wrong in my derivation of the friction.This is what I thought F=-k\dot{x}^2 \hat{\textbf{v}} \hat{\textbf{v}}=\dfrac{\textbf{v}}{||\textbf{v}||}=\dfrac{(\dot{x})}{\dot{x}}=(1) Where the brackets denote a vector in the x direction. Now...