The network shown in the
figure represents a simple power transmission system.
The generator produces 60 Hz and is modeled by a simple Thévenin equivalent.The transmission line consists of a long length of copper wire and can be accurately described as a 50Ω resistor.
Determine the load current
${R}_{\text{L}}$ and the average power the generator must produce so that the load receives 1,000 watts of average power.
Why does the generator need to generate more than 1,000 watts of average power to meet this requirement?
Suppose the load is changed to that shown in the second
figure .
Now how much power must the generator produce to meet the same power requirement?Why is it more than it had to produce to meet the requirement for the resistive load?
The load can be
compensated to have a unity
power factor (see
exercise ) so that the voltage and current are in phase for maximum power efficiency.
The compensation technique is to place a circuit in parallel to the load circuit. What element works and what is its value?
With this compensated circuit, how much power must the generator produce to deliver 1,000 average power to the load?
Optimal power transmission
The following
figure shows a general model for power transmission.
The power generator is represented by a Thévinin equivalent and the load by a simple impedance.In most applications, the source components are fixed while there is some latitude in choosing the load.
Suppose we wanted the maximize "voltage transmission:"
make the voltage across the load as large as possible.What choice of load impedance creates the largest load voltage?
What is the largest load voltage?
If we wanted the maximum current to pass through the load, what would we choose the load impedance to be?
What is this largest current?
What choice for the load impedance maximizes the average power dissipated in the load?
What is most power the generator can deliver?
One way to maximize a function of a complex variable is to write the expression in terms of the variable's real and imaginary parts, evaluate derivatives with respect to each, set both derivatives to zero and solve the two equations simultaneously.
Big is beautiful
Sammy wants to choose speakers that produce very loud music.
He has an amplifier and notices that the speaker terminals are labeled"
$8\Omega $ source."
What does this mean in terms of the amplifier's equivalent circuit?
Any speaker Sammy attaches to the terminals can be well-modeled as a resistor.
Choosing a speaker amounts to choosing the values for the resistor.What choice would maximize the voltage across the speakers?
Sammy decides that maximizing the power delivered to the speaker might be a better choice.
What values for the speaker resistor should be chosen to maximize the power delivered to the speaker?
Sharing a channel
Two transmitter-receiver pairs want to share the same
digital communications channel. The transmitter signalswill be added together by the channel. Receiver design
is greatly simplified if first we remove the unwantedtransmission (as much as possible). Each transmitter
signal has the form
$$\forall t, 0\le t\le T\colon {x}_{i}(t)=A\sin (2\pi {f}_{i}t)$$ where the amplitude is either zero or
$A$ and each transmitter uses its own frequency
${f}_{i}$ .
Each frequency is harmonically related to the bitinterval duration
$T$ ,
where the transmitter 1 uses the the frequency
$\frac{1}{T}$ .
The datarate is 10Mbps.
Draw a block diagram that expresses this
communication scenario.
Find circuits that the receivers could employ to
separate unwanted transmissions. Assume the receivedsignal is a voltage and the output is to be a
voltage as well.
Find the second transmitter's frequency so that the
receivers can suppress the unwanted transmission byat least a factor of ten.
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
Tarell
what is the actual application of fullerenes nowadays?
Damian
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
Tarell
what is the Synthesis, properties,and applications of carbon nano chemistry
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Harper
Do you know which machine is used to that process?