# Search results

1. ### I Density of States Derivation

Thanks, i've been plugging in ##\ \hbar = {h\over\pi}##.
2. ### I Density of States Derivation

I was looking for a derivation for the density of states and I came across this page: https://ecee.colorado.edu/~bart/book/book/chapter2/ch2_4.htm I followed the derivation and came up with: g(E) = (1/L3)dN/dE = (1/L3)L3/∏2*k2 * dk/dE =K2/∏2 * dk/dE =K2/∏2 * g(E) =...
3. ### Spark in relay contacts

Thank you for answering my questions. :D
4. ### Spark in relay contacts

With an inductive load, abrupt current interruption or variation induces a high voltage. I couldn't see how it can happen with a purely resistive circuit. After reading your replies, my understanding is that a spark could jump if the relay contacts are extremely close to each other, which...
5. ### Spark in relay contacts

Why is there a spark in the relay contacts? Suppose that the coil and the contacts are connected to two different power supplies. If i suddenly disconnect the power supply to the coil, then the voltage across the coil will increase and a spark will jump across the switch that I used to...
6. ### Admissions How to pay for Masters in the US

I am a US citizen. I was born in New York but I grew up in the Philippines. I am planning to take my Masters in Electrical Engineering specializing in IC design or Control Systems in the US, but when I checked the tuition/fees I learned that it would take a crazy amount of time to save up that...

Thanks for answering my questions. I have a degree in Electronics Engineering. I'll follow your advice to take up graduate school in the US. For now, I still have to work and save money to study in the US. Can I just take my MS here and take my Ph.D in the US, or would that be more difficult?

I have recently passed the Electronics Engineering Licensure exam in the philippines and I'm plannning to pursue a career in chip design preferrably mixed signal or digital. I have applied at different semiconductor companies. The problem is they don't design the IC's here, they only conduct...
9. ### Why does vacuum have resistance?

Thanks. Haha, I didn't realize that.
10. ### Why does vacuum have resistance?

Suppose that there is a positively charged particle and a negatively charged particle in free space. The electric field of the positive charge causes a difference in potential between the position of the negatively charged particle and the positively charged particle. This, causes the negatively...
11. ### Amplitude modulation and amplifier efficiency

These are sample problems from Blake's electronic comms book: 1.) A transmitter has a carrier power output of 10W at an efficiency of 70%. How much power must be supplied by the modulating amplifier for 100% modulation Book Solution: efficiency=Po/Ps (I don't know what Po is...
12. ### Amplitude modulation and amplifier efficiency

" A intelligence signal is amplified by a 80% efficient amplifier before being combined with a 12kW carrier to generate the AM signal. if it is desired to operate at 100% modulation, what is the DC input power at the modulator" The choices are a: 12kW b. 7.14kW c.7.5kW d. 15kW my solution...
13. ### How is a memristor different from a resistor

So M is not a constant unlike R, L, and C? I read that the memristor was predicted due to the symmetry of the equations for R, L and C. If M is not constant with respect to time, doesn't that make the memristor the odd one out o the four, so that there is still no symmetry?
14. ### How is a memristor different from a resistor

I read that the memristor is described by the equation dφ=Mdq. If both sides are divided by dt, then dφ/dt=Mdq/dt. But dφ/dt=V and dq/dt=I. Then V=MI which is ohm's law. Isn't the constant M just the same as resistance?
15. ### Problem with Minimum Nyquist bandwidth formula and m-ary encoding

I am using the book Electronic Communication Systems by Wayne Tomasi: I had a problem with a certain part of the book: The book gives the formula for the minimum nyquist bandwidth as: " The minimum theoretical bandwidth necessary to propagate a signal is called the minimum Nyquist bandwidth...

thanks!!
17. ### How do i find the principal form of this complex number

How? That's exactly what my problem is. 10-j and elogj aren't similar to any of the forms discussed in school. Can you give another hint?
18. ### How do i find the principal form of this complex number

the principal form is defined in my book as ln(z)=ln(r)+jθ
19. ### How do i find the principal form of this complex number

z= (10-j+elogj)2 I tried expanding but it just made it more complicated. help please!!
20. ### Effects of dc beta(hfe) in BJT characteristics

Here's the image
21. ### Effects of dc beta(hfe) in BJT characteristics

In our experiment the base current was considered as the input, and the collector current as the output.The voltage Vbb being fed across the base and emitter was controlled to establish a fixed base current. We set the base current to be equal to 50 micro amps, then 100 and 150. Then A voltage...
22. ### Effects of dc beta(hfe) in BJT characteristics

I can't upload the file, I made it with paint but it exceeds the limit for file size. The bjt configuration has a variable dc source and resistor connected to each of the collector and base
23. ### Effects of dc beta(hfe) in BJT characteristics

I need help in answering the post lab questions given to us by our professor. 1. Is dc beta constant on every point of the characteristics? What is its effect in the linearity of the transistor? 2. What is the effect of a high dc beta on the characteristic curves? I have attached an...
24. ### Vector analysis textbook

Can you suggest me a book in vector analysis which covers spherical and cylindrical coordinates. My professor discusses the calculation of volume, surface area and curve length, by integrating differential surface and volume elements in terms of cartesian, spherical and cylindrical coordinates...
25. ### How to use a rocker switch with three or four terminals

I've watched this youtube video : , and understood it only a little so i came here for help. How does that three terminal rocker switch work. It says that the terminals are for power, ground and acc.(Is acc accessory which means load??) If for example, i want the switch to control a simple...
26. ### Help Input output characteristics of BJT

i can't attach the pic so i'll jusr give the link http://comutronics.blogspot.com/2012/02/ece-basic-interview-question-and_06.html [Broken]
27. ### Help Input output characteristics of BJT

help!! Input output characteristics of BJT I have attached an image of the graph. Does this graph apply for both npn and pnp transistors. I have asked this because for pnp, the collector(c) and base(B) terminals must be reverse-biased at the active region, and B must be at a higher potential...