hi guys
I am attempting to solve a problem that has me scratching my head. I have a small connector PCB with one 8k resistor present. The connector is four way with the resistor terminals being the two inner pads. The outer two pads are short circuit together.
I solder two wires on the...
hi there
I am currently working with linear flows and using a ultrasonic setup to determine the speed of sound in a linear gaseous flow. But I would like to know more about the speed of sound in a vortical flow. Unfortunately I haven't been able to find any good book with regard to my topic...
hi
I know the Fourier transform of a lorentzian function is a lorentzian but i was wondering if the Fourier transform of the second derivation of a lorentzian function is also a second derivative of a lorentzian function
Thanks
hi
the differential equation i am attempting to solve is:
\frac {dP} {dx} = \frac {gP} {1+P/Psat}
here is what I have done:
\frac {dP} {dx} = \frac {gP*Psat} {Psat+P}
divide both sides by \frac {Psat+P} {gP*Psat}
to get:
\frac {Psat+P} {P*Psat} \frac {dP} {dx} =g...
sketch the spectrum of the PAM signal S(f) if the input is m(t)=cos(2*pi*fm*t) where fm=3000 at a sampling rate of 10000 using rectangular pulses of duration 0.04ms. in the range +-15Khz
S(f)=H(f)*M'(f)
taking the Fourier transform of the rectangular pulse we obtain: H(f)=Tsinc(Tf) where...
what does normalization mean?
for example say i have the guassian input as :
A(0,T) = \sqrt{Po}*exp(-T^2/2To^2)
then we can normalize it by defining t=T/To and A(z,T) = \sqrt{Po}U(z,t)
Po= peak power t= normalized to the input pulse width To. if the peak of the pulse is...
Hey guys, I have a good job lined up for me after I graduate with a good company, i am currently 8 months away from graduation. I have a diffcult desicion to make about my final year project. I have been offered projects from two companies and one of them is the one i start working for at the...
Hi
i was wondering what's is the difference between electromagnetic waves and fields or is a field just a number of electromagnetic waves. also i was wondering is it possbile to have an electromagnetic wave where there is only a magnetic field and no electric field and vice versa
Thanks
Hi
if i have a voltage supply of 100V connected across a 66 ohm resistor which has a power rating of 155W. then P=V^2/R=10000/66=151W but say if i had the same situation except i add another resistor in series to increase the resistance of the overall circuit by adding a 100 ohm resistor...
well i connected a 0.1uH inductor to a signal generator which generated 5V ac voltage and then i added a resistor connected to the inductor and ground.
then i measured the voltage across the 10 ohms resistor on a oscilloscope and at was the same as the input so that's why i wondering if i...
hi
i was wondering if we would treat inductors and capacitors as short circuits for AC voltages. i am aware that there is a 90 degrees phase shift in a RC or RL circuit with an ac voltage but the phase shift only applies to the current.
thanks
hi there i am looking for monochromatic colored filters like on the picture on the following web page:
http://en.wikipedia.org/wiki/File:Filter-optics-1.jpg
(preferably with no reflectivity)
but i have had no luck trying to find them while looking on google
hi
i bought a machine which determines led colours by measuring intensity for a product.
the product has three leds:green,red,orange. the equipment works well for the green and red leds but fails most of the time with the orange leds. i looked up wavelength values for the colours and i...
thats super cheap and awesome bassalisk i going to order one after i test the one i am building and colin thanks for the tip i have ordered a 18-pin IC pin socket. do you think it would be safe to put the cct together on a breadboard and connect to my pc via the RS232 female connecter
lol i just found this out and it works for the PIC i am working on apparently,its really easy to make and so i am going to attempt to make it check it out:
http://www.instructables.com/id/How-to-make-the-worlds-smallest-and-cheapest-PIC-/?&sort=ACTIVE&limit=40&offset=40
i have just been reading up on pickit3 programmer but it seems like it you would have to solder the complete circuit together before you program it using the pickit3 by connecting to the pc via usb and you would also need to provide two I/O pins for the pickit3 to connect to the board is this...
hello
i have been learning about micro-controllers for about a month now and i have started my own private projects using them. at the moment i am using a PIC micro controller for a alarm clock which is programmed in C. I have ordered the parts and designed the pcb but i have had some...
hi there
i have been reading up on the function of pull up resistors from the text:http://ti.tuwien.ac.at/ecs/teaching/courses/mclu/theory-material/Microcontroller.pdf and on page 37 it talks about it. in their example of the pull up resistor with the switch. i was wondering if they circuit...
the output end is connected straight into a micro controller model p80C557E (at the interrupt pin) i am not really familiar with micro controllers but should the load be the internal resistance of the microcontroller?
hi there
i just have a question about diodes say for example we have the following cct:
the circuit with the diodes with the 5V supply, one of the diodes is on and the other off and i understand why this happens but when dealing with the circuit the opamp and the diode i am confused. the...
Homework Statement
Consider a Fabry-Perot laser, length 0.1m, with an unsaturated gain coefficient, \gammao=1m-1
one of the mirrors of the Fabry-Perot cavity is perfectly reflecting, the other reflects 95% of the light and transmits 5%. wit the aid of a brief calculation explain why steady...
Homework Statement
consider a two level atomic system , solve the rate equations for the two levels to find expressions for N1(t) and N2(t) in terms of the intial populations N1(0) and N2(0)
Homework Equations
i have been able to derive the rate equations as...
Homework Statement
for my assignment given i was told to derive the equation of the skin depth of a good conductor and i derived it as
d=sqrt(2/\mu\omega\sigma)
then i was told to calculate d where i was given w=10^15 and sigma=10^7 and this gave me a d of d=1.26E-8 which i guess is...
hi
i need help with some pi matching for the following cct shown below, i would usually approach this problem with X=sqrt(1000*50) where X is the reactance of L1,C2,C3 but since C1 is in this cct then i can't use this equation so could someone please help me solve this problem
ugh well if i do it analytically and perform small signal analysis would it be correct to short cct the DC source and short circuit the coupling capacitors and also the capacitor in parallel with the base resistor and inductor. then the output impedance will be completely reactive and given by...
hi
i want to find the output impedance of the following cct so i can perform pi matching on it but i don't know how to find it using lt spice please help!
added schematic
hi
i would like to bias a transistor into cutoff. i have the schematic shown below and for the transistor i am using it has a collector cutoff current at 100nA. so my approach was frist to perform Dc analysis:
Vth=5*(R10/(R10+R4)) Rth=(R4*R10)/(R10+R4)
so my input equation is...
omg i can't believe i did not see that. i have now attached the resistors to the base and this the output i get (red/green graph where input is red and output green):
i wasnt sure to measure the dc voltage using ltspice so i plotted the base voltage against the emitter voltage (...
hi again
i tried decreasing the size of the top base resistor but it didnt work so i tried changing the capacitor values and now my output looks like this(output is the green colour). so is the buffer working because in your above statement you said
If the output is exactly like the input...
i have designed the buffer to have a input impedance of 57.4k, output impedance of 50.9 ohms and gain of 0.99 are those specs good for a buffer and by the way this is the output i get from ltspice
hi
i am having my frist attempt on designing a common- collector transistor buffer which has a unity gain of 1. i am using lt spice to check the input and output of my buffer, however i am not sure how to determine if my buffer is working. if my input is a square wave with 3 volt amplitude...
hello
i have been given six weeks to design a low-power FM radio transmitter for my project however there are no lectures for this course so i have to do the research on my own. so far from researching on the web. i have found that a simple radio transmitter may consist of a number of stages...
\GammaHomework Statement
if an electric field is traveling in air and hits a medium n2. then there will be three fields present:
the incident electric field
the reflected electric field
and the transmitted electric field.
the electric field in medium 1 would be...
thanks for the clear demonstration. so i was wondering if i had a choice between a half wave dipole and a 3 half wave dipole to design. then i should design a 3 half wave dipole antenna because it will have a higher gain ?
Homework Statement
i just have a few questions about the radiation pattern of a half wave dipole antenna.
firstly i know the for the half wave dipole we can dervie and expression for the electric field in the zenith angle and the magnetic field in the azimutal angle by using the far field...
Homework Statement
hi i have been given the following electric field phasor E=(z(5)+x(10))e-jpi(y) mV/m
Mr=100
er=3
Homework Equations
The Attempt at a Solution
i have been able to deduce from the results above that wave is traveling in positive y direction.
intrinsic...
Homework Statement
for the vector field E=x(xy)-y(x^2 +2y^2)
find E.dl along the contour
find (nabla)xE along the surface x=0 and x=1 y=0 and y=1
Homework Equations
The Attempt at a Solution
i tried the second question (nabla)xE over the surface by finding the...
Homework Statement
A 8-point data set is transformed with a DFT and the resulting array has values
1,2,3,4,5,6,7,8
was the data set real or complex? why?
Homework Equations
The Attempt at a Solution
kind of confused with this question all i know is the discrete Fourier...
Homework Statement
An ADC system samples at frequency of 500Hz. it is preceded by 4-pole low_pass Butterworth filter having a 3db frequency of 1KHZ. Three intefering signals are present at frequencies of 2kHz,2.6kHz and 4.4kHz
a) what is the Nyquist frequency of the process?
b) what will...