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?
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
Discuss the differences between taste and flavor, including how other sensory inputs contribute to our perception of flavor.
The lymphatic system plays several crucial roles in the human body, functioning as a key component of the immune system and contributing to the maintenance of fluid balance. Its main functions include:
1. Immune Response: The lymphatic system produces and transports lymphocytes, which are a type of
asegid
to transport fluids fats proteins and lymphocytes to the blood stream as lymph
Anatomy is the study of the structure of the body, while physiology is the study of the function of the body. Anatomy looks at the body's organs and systems, while physiology looks at how those organs and systems work together to keep the body functioning.
Enzymes are proteins that help speed up chemical reactions in our bodies. Enzymes are essential for digestion, liver function and much more. Too much or too little of a certain enzyme can cause health problems
Kamara
yes
Prince
how does the stomach protect itself from the damaging effects of HCl
the normal temperature is 37°c or 98.6 °Fahrenheit is important for maintaining the homeostasis in the body
the body regular this temperature through the process called thermoregulation which involves brain skin muscle and other organ working together to maintain stable internal temperature