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
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?
Simple power transmission system
Modified load circuit
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"
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
where the amplitude is either zero or
and each transmitter uses its own frequency
.
Each frequency is harmonically related to the bitinterval duration
,
where the transmitter 1 uses the the frequency
.
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.
Questions & Answers
A golfer on a fairway is 70 m away from the green, which sits below the level of the fairway by 20 m. If the golfer hits the ball at an angle of 40° with an initial speed of 20 m/s, how close to the green does she come?
A mouse of mass 200 g falls 100 m down a vertical mine shaft and lands at the bottom with a speed of 8.0 m/s. During its fall, how much work is done on the mouse by air resistance
Chemistry is a branch of science that deals with the study of matter,it composition,it structure and the changes it undergoes
Adjei
please, I'm a physics student and I need help in physics
Adjanou
chemistry could also be understood like the sexual attraction/repulsion of the male and female elements. the reaction varies depending on the energy differences of each given gender. + masculine -female.
Pedro
A ball is thrown straight up.it passes a 2.0m high window 7.50 m off the ground on it path up and takes 1.30 s to go past the window.what was the ball initial velocity
2. A sled plus passenger with total mass 50 kg is pulled 20 m across the snow (0.20) at constant velocity by a force directed 25° above the horizontal. Calculate (a) the work of the applied force, (b) the work of friction, and (c) the total work.
you have been hired as an espert witness in a court case involving an automobile accident. the accident involved car A of mass 1500kg which crashed into stationary car B of mass 1100kg. the driver of car A applied his brakes 15 m before he skidded and crashed into car B. after the collision, car A s
can someone explain to me, an ignorant high school student, why the trend of the graph doesn't follow the fact that the higher frequency a sound wave is, the more power it is, hence, making me think the phons output would follow this general trend?
Nevermind i just realied that the graph is the phons output for a person with normal hearing and not just the phons output of the sound waves power, I should read the entire thing next time
Joseph
Follow up question, does anyone know where I can find a graph that accuretly depicts the actual relative "power" output of sound over its frequency instead of just humans hearing
Joseph
"Generation of electrical energy from sound energy | IEEE Conference Publication | IEEE Xplore" ***ieeexplore.ieee.org/document/7150687?reload=true
A string is 3.00 m long with a mass of 5.00 g. The string is held taut with a tension of 500.00 N applied to the string. A pulse is sent down the string. How long does it take the pulse to travel the 3.00 m of the string?
