In the lab, the open-circuit voltage measured across an
unknown circuit's terminals equals
.
When a 1Ω resistor is place across the terminals, avoltage of
appears.
What is the Thévenin equivalent circuit?
What voltage will appear if we place a 1F capacitor
across the terminals?
Mystery circuit
We want to determine as much as we can about the circuit lurking in the impenetrable box shown in
[link] .
A voltage source
V
has been attached to the left-hand terminals, leaving the right terminals for tests and measurements.
Sammy measures
V when a 1 Ω resistor is attached to the terminals.
Samantha says he is wrong.Who is correct and why?
When nothing is attached to the right-hand terminals, a voltage of
V is measured.
What circuit could produce this output?
When a current source is attached so that
amp, the voltage
is now 3 V.
What resistor circuit would be consistent with this and the previous part?
More circuit detective work
The left terminal pair of a two
terminal-pair circuit is attached to a testingcircuit. The test source
equals
(
[link] ).
We make the following measurements.
With nothing attached to the terminals on the
right, the voltage
equals
.
When a wire is placed across the terminals on
the right, the current
was
.
What is the impedance “seen” from the terminals
on the right?
Find the voltage
if a current source is attached to the
terminals on the right so that
.
Linear, time-invariant systems
For a system to be completely characterized by atransfer function, it needs not only be linear, but also
to be time-invariant. A system is said to betime-invariant if delaying the input delays the output
by the same amount. Mathematically, if
,
meaning
is the output of a system
when
is the input,
is the time-invariant if
for all delays
and all inputs
.
Note that both linear and nonlinear systems have thisproperty. For example, a system that squares its input
is time-invariant.
Show that if a circuit has fixed circuit elements
(their values don't change over time), itsinput-output relationship is time-invariant.
Hint : Consider the differential
equation that describes a circuit's input-outputrelationship. What is its general form? Examine the
derivative(s) of delayed signals.
Show that impedances cannot characterize
time-varying circuit elements (R, L, and C).Consequently, show that linear, time-varying systems
do not have a transfer function.
Determine the linearity and time-invariance of the
following. Find the transfer function of the linear,time-invariant (LTI) one(s).
diode
Long and sleepless nights
Sammy went to lab after a long, sleepless night, and
constructed the circuit shown in
[link] .
He cannot remember what the circuit, represented by theimpedance
, was. Clearly,
this forgotten circuit is important as the output is thecurrent passing through it.
What is the Thévenin equivalent circuit seen by
the impedance?
In searching his notes, Sammy finds that the circuitis to realize the transfer function
Find the impedance
as well as values for the other circuit elements.
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1. Immune Response: The lymphatic system produces and transports lymphocytes, which are a type of
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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