What is the impedance
at the frequency of
the source?
Black-box circuit
You are given a
circuit that has two terminals for
attaching circuit elements.
When you attach a voltage source equaling
to the terminals, the current through the source equals
.
When no source is attached (open-circuited terminals),the voltage across the terminals has the form
.
What will the terminal current be when you replace thesource by a short circuit?
If you were to build a circuit that was identical
(from the viewpoint of the terminals) to the givenone, what would your circuit be?
For your circuit, what are
and
?
Solving a mystery circuit
Sammy must determine as much as he can about a mystery
circuit by attaching elements to the terminal andmeasuring the resulting voltage. When he attaches a 1Ω
resistor to the circuit's terminals, he measuresthe voltage across the terminals to be
.
When he attaches a 1F capacitor across the terminals,the voltage is now
.
What voltage should he measure when he attaches
nothing to the mystery circuit?
What voltage should Sammy measure if he doubled the
size of the capacitor to 2 F and attached it to thecircuit?
Find the load impedance
The
depicted circuit has a transfer function between the
output voltage and the source equal to
.
Sketch the magnitude and phase of the transfer
function.
At what frequency does the phase equal
?
Find a circuit that corresponds to this loadimpedance. Is your answer unique? If so, show it to be
so; if not, give another example.
Analog “hum” rejection
“Hum” refers to corruption from wall socket
power that frequently sneaks intocircuits. “Hum” gets its name because it
sounds like a persistent humming sound. We want to finda circuit that will remove hum from any signal. A Rice
engineer suggests using a
simple voltage divider circuit consisting of two series impedances.
The impedance
is a resistor. The Rice engineer must decide between
two circuits for the impedance
.
Which of these will work?
Picking one circuit that works, choose circuit elementvalues that will remove hum.
Sketch the magnitude of the resulting frequency
response.
An interesting circuit
For the circuit shown in
[link] ,
find the transfer function.
What is the output voltage when the input has the form
?
What is the transfer function between the source and
the output voltage?
What will the voltage be when the source equals
?
Many function generators produce a constant offset in
addition to a sinusoid. If the source equals
,
what is theoutput voltage?
An interesting and useful circuit
The
depicted circuit has interesting properties, which
are exploited in high-performance oscilloscopes.
The portion of the circuit labeled "Oscilloscope"
represents the scope's input impedance.
and
(note the label under the channel 1 input in the lab'soscilloscopes). A
probe is a device
to attach an oscilloscope to a circuit, and it has theindicated circuit inside it.
Suppose for a moment that the probe is merely a wire
and that the oscilloscope is attached to a circuitthat has a resistive Thévenin equivalent
impedance. What would be the effect of theoscilloscope's input impedance on measured voltages?
Using the node method, find the transfer function
relating the indicated voltage to the source whenthe probe is used.
Plot the magnitude and phase of this transfer
function when
and
.
For a particular relationship among the elementvalues, the transfer function is quite simple. Find
that relationship and describe what is so specialabout it.
The arrow through
indicates that its value can be varied. Select the
value for this capacitor to make the specialrelationship valid. What is the impedance seen by
the circuit being measured for this special value?
Wayne and Dennis like to ride the bike path from Riverside Park to the beach. Dennis’s speed is seven miles per hour faster than Wayne’s speed, so it takes Wayne 2 hours to ride to the beach while it takes Dennis 1.5 hours for the ride. Find the speed of both bikers.
from theory: distance [miles] = speed [mph] × time [hours]
info #1
speed_Dennis × 1.5 = speed_Wayne × 2
=> speed_Wayne = 0.75 × speed_Dennis (i)
info #2
speed_Dennis = speed_Wayne + 7 [mph] (ii)
use (i) in (ii) => [...]
speed_Dennis = 28 mph
speed_Wayne = 21 mph
George
Let W be Wayne's speed in miles per hour and D be Dennis's speed in miles per hour. We know that W + 7 = D and W * 2 = D * 1.5.
Substituting the first equation into the second:
W * 2 = (W + 7) * 1.5
W * 2 = W * 1.5 + 7 * 1.5
0.5 * W = 7 * 1.5
W = 7 * 3 or 21
W is 21
D = W + 7
D = 21 + 7
D = 28
Salma
Devon is 32 32 years older than his son, Milan. The sum of both their ages is 54 54. Using the variables d d and m m to represent the ages of Devon and Milan, respectively, write a system of equations to describe this situation. Enter the equations below, separated by a comma.
please why is it that the 0is in the place of ten thousand
Grace
Send the example to me here and let me see
Stephen
A meditation garden is in the shape of a right triangle, with one leg 7 feet. The length of the hypotenuse is one more than the length of one of the other legs. Find the lengths of the hypotenuse and the other leg
however, may I ask you some questions about Algarba?
Amoon
hi
Enock
what the last part of the problem mean?
Roger
The Jones family took a 15 mile canoe ride down the Indian River in three hours. After lunch, the return trip back up the river took five hours. Find the rate, in mph, of the canoe in still water and the rate of the current.
Shakir works at a computer store. His weekly pay will be either a fixed amount, $925, or $500 plus 12% of his total sales. How much should his total sales be for his variable pay option to exceed the fixed amount of $925.
I'm guessing, but it's somewhere around $4335.00 I think
Lewis
12% of sales will need to exceed 925 - 500, or 425 to exceed fixed amount option. What amount of sales does that equal? 425 ÷ (12÷100) = 3541.67. So the answer is sales greater than 3541.67.
Check:
Sales = 3542
Commission 12%=425.04
Pay = 500 + 425.04 = 925.04.
925.04 > 925.00
Munster
difference between rational and irrational numbers
Jazmine trained for 3 hours on Saturday. She ran 8 miles and then biked 24 miles. Her biking speed is 4 mph faster than her running speed. What is her running speed?