Transcript File

TRANSDUCERS
• Device that converts one form of energy to
another form for various purposes including
measurement or information transfer.
• Energy may be of any kind electrical,
mechanical, chemical, optical.
Basic Requirements of transducers
• Linearity : i/p – o/p characteristics should
be linear.
• Stability : o/p should be stable to change in temp
& other environmental factors.
• Ruggedness : capable of withstanding overloads,
with measures of overload protection.
• Repeatability : should produce identical output signals.
• Dynamic Response: should respond to changes in i/p as
quickly as possible.
• Reliability: should withstand mechanical strains without
affecting the performance of the transducer.
Classification of Transducers
• Active Transducers
self generating, does
not require external
source.



Thermocouple
Photovoltaic Cell
Piezoelectric Transducer
• Passive Transducer
Requires an external
power source.

Resistive Transducer
Strain Gauge, Thermister,
Thermometer.

Inductive Transducer
Linear Variable Differential
Transducer

Capacitive Transducer
Photoemissive Cell
Photomultiplier Tube
Strain Gauge
• A device whose electrical resistance varies in
proportion to the amount of strain in the device.
• The sensitivity of stain gauge is described in terms of
Gauge factor.
• Gauge factor-Change in resistance per unit change in
length.
G = ΔR/R = ΔR/R
Δl/l
S
Bonded strain gauge
• Consist of a grid of fine resistance wire cemented to
the base.
• Base may be thin sheet of paper or bakelite.
• Covered with thin sheet of paper or thin bakelite sheet
to avoid mechanical damage.
• Bonded to the structure under study with
an adhesive.
Bonded Strain gauge
Unbonded strain gauge
• Unbonded strain gages consist of a wire stretched
between two points
• Force acting on the wire (area = A, length = L,
resistivity = r) will cause the wire to elongate or
shorten.
• This will cause the resistance to increase or
• decrease proportionally according to:
R = ρL/A
and
ΔR/R = GF· ΔL/L,
where GF = Gauge factor (2.0 to 4.5 for metals, and
more than 150 for semiconductors).
Unbonded Strain Gauge
Thermistor
• Two terminal resistor whose resistance changes
significantly when its temperature changes.
• The resistance of a thermistor decreases with increase
of temperature.
• Resistance at any temp is given by
RT=R0 exp β(1/T-1/T0)
Where RT = thermister resistance at temp T(K)
R0 = thermister resistance at temp T0(K)
β = A constant determined by calibration.
Miniature Epoxy Coated Thermistors
Symbol
• Three parameters characterizing the thermistor are



Time Constant - time for thermistor to change its
resistance by 63%.(1 to 50ms)
Dissipation Constant - power necessary to increase the
temp of thermistor by 1ºC.(1 to 10 mW/ºC)
Resistance Ratio - ratio of resistance at 25ºC to that at
125ºC.(3 TO 60).
• Uses:
To measure temp, flow, pressure, composition
of gases, liquid level etc.
Thermocouple
• Junction between to dissimilar metals or
semiconductors that generates a small voltage.
• The two junctions reference and sensing are
maintained at different temp.
• Each junction is made by welding the two dissimilar
metals together.
• Reference junction has a fixed temp usually 0ºC.
• And the output voltage depends on the temp of
sensing junction.
Thermocouple circuit
iron
Reference
junction
constantan
iron
Milli voltmeter
constantan
Sensing
junction
Inductive Transducers
• In the first diagram the variable inductor is part of an
oscillator circuit.
• If the position of the core is moved then the oscillator
frequency changes.
• The change in frequency can be displayed as a change
in millimetres.
variable inductance type
Variable reluctance type
• As the air gap changes the reluctance of the circuit
changes.
• This causes a change of inductance.
• This can be used as shown by the next illustration.
• As the inductance changes so the frequency of the
oscillator changes.
• The output of the oscillator can be converted to DC
for display on a digital meter calibrated in inches etc.
Linear Variable Differential
Transformer
• There is one primary and two secondary windings.
• If AC is applied to the primary then voltages are
induced in the secondaries.
• The secondaries are connected so their outputs are
opposite.
• When the core is central the two voltages are equal in
amplitude and cancel out.
LVDT
• If the core is moved then there will be more voltage
in one secondary than the other.
• The voltages will not cancel out and there will be an
AC signal at the output proportional to the distance
the core has moved.
• Using a phase detector circuit it is also possible to
indicate the direction the core has moved.
• The graph representation shows the output
voltage/position characteristics.
LVDT
Model Graph
Load Cell
• A load cell is typically an electronic device
that is used to convert a force into an electrical
signal.
• This conversion is indirect and happens in two
stages.


Through a mechanical arrangement, the force
being sensed deforms a strain gauge.
The strain gauge converts the deformation (strain)
to electrical signals.
• Normally, a load cell consists of four strain
gauges in a Wheatstone bridge configuration,
but is also available with one or two strain
gauges.
• The electrical signal output is normally in the
order of a few millivolts and requires
amplification by an instrumentation amplifier
before it can be used.
• The output of the transducer is plugged into an
algorithm to calculate the force applied to the
transducer.
Pyrometer
• It’s a non-contact instrument that detects an object's
surface temperature by measuring the temperature of
the electromagnetic radiation (infrared or visible)
emitted from the object.
• The wavelength of thermal radiation ranges from 0.1
to 100 µm i.e., from the deep ultraviolet (UV) across
the visible spectrum to the middle of the infrared
region (IR).
• Pyrometers are
essentially photo
detectors which are
capable of absorbing
energy, or measuring
the EM wave intensity,
at a particular
wavelength or within a
certain range of
wavelengths.
• Common pyrometers include:
 Optical Pyrometer :
- Designed for thermal radiation in the visible spectrum.
- Utilizes a visual comparison between a calibrated light
source and the targeted surface.
- When the filament and the target have the same
temperature, their thermal radiation intensity will match
causing the filament to disappear as it blends into the
targeted surface in the background.
- When the filament disappears, the current passing
through the filament can be converted into a
temperature reading.

Infrared Pyrometer:
- Designed for thermal radiation in the infrared
region usually 2 ~ 14 µm
- Constructed from pyroelectric materials, e.g.,
triglisine sulfate (TGS), lithium tantalate (LiTaO3),
or polyvinylidene fluoride (PVDF).
- Similar to the charge generated by stressed
piezoelectric materials, a pyroelectric charge
dissipates in time.
- Hence, a rotating shutter is required to interrupt the
incoming radiation to obtain a stable output.
• Advantages:
– Fast response time
– Good stability
– Non-contact measurement
• Disadvantages:
– Expensive
– Accuracy maybe affected by suspended dust, smoke,
and thermal background radiation
The Variable Area flowmeter
• Also known as Rotameter, is one of the most
economical and reliable of flow measurement
instruments.
• In various configurations it can be designed to
withstand high pressures, corrosive fluids, high
temperatures, and is completely independent of
factors influencing electronic meters.
• This is done using a uniformly tapered tube, a float
whose diameter is nearly identical to the tube ID at
the inlet, and a scale to correlate float height.
Variable Area Flowmeter
• The flow tube is traditionally placed in a vertical
position and fluid enters from the bottom, forcing the
float up in the tube until a sufficient annular opening
exists between the float and tube to allow the total
volume of fluid to flow past the float.
• At this point the float is in an equilibrium position
and its height is proportional to the flow rate.
CLASSIFICATION OF
MEASURING INSTRUMENTS
Depending on working principle
•
Moving iron type
instruments
a). Attraction type
b). Repulsion type
• Moving coil type
instruments
a). Permanent magnet
type
b). Dynamometer type
MOVING IRON INSTRUMENTS – ATTRACTION TYPE
Principle
• A soft iron piece gets magnetized when it is brought into a magnetic
field produced by a permanent magnet.
• The same phenomenon happens when the soft iron piece is brought
near either of the ends of a coil carrying current.
• The iron piece is attracted towards that portion where the magnetic flux
density is more.
• This movement of soft iron piece is used to measure the current or
voltage which produces the magnetic field.
Construction
• A soft iron disc is attached
to the spindle
• To the spindle, a pointer is
also attached, which is made
to move over calibrated
scale
• The moving iron is pivoted
such that it is attracted
towards the center of the
coil where the magnetic
field is maximum
Principle
• When the current to be measured is passed
through the coil or solenoid, field is produced
which attracts the eccentrically mounted disc
inwards, thereby deflection the pointer which
moves over a calibrated scale
Deflecting Torque
•
•
•
•
Produced by the current or the voltage to be measured.
It is proportional to the square of the voltage or current.
Hence, the instrument can be used to measure d.c. or a.c.
Scale is non- uniform
Control torque : Spring or gravity
Damping
: Air friction damping
MOVING IRON INSTRUMENT - REPULSION
TYPE
Principle
• Two iron piece kept with close proximity in a
magnetic field get magnetized to the same polarity.
Hence, a repulsive force is produced.
• If one of the two piece is made movable, the repulsive
force will act on it and move it on to one side.
• This movement is used to measure the current or
voltage which produces the magnetic field.
Construction
•
•
There are two iron pieces-fixed and moving.
The moving iron is connected to the spindle to
which is attached a pointer. It is made to move over a
calibrated scale.
Working
• When the current to be measured is passed through the fixed
coil it sets up its own magnetic field which magnetizes the two
rods similarly the adjacent points on the lengths of the rods
will have the same magnetic polarity.
• Hence, they repel each other with the result that the pointer is
deflected against the controlling torque of a spring or gravity.
• The force of repulsion is approximately proportional to the
square of the current passing through the coil
• Whatever be the direction of current in the coil, the two irons
are always similarly magnetised.
Deflecting torque
• Produced by the current or the voltage to be measured.
• It is proportional to the square of the voltage or current.
• Hence, the instrument can be used to measure d.c. or a.c.
Control torque : Spring or gravity
Damping
: Air friction damping
Advantages and disadvantages:
• The instruments are cheap ,reliable and robust
• The instruments can be used on both A.C and
D.C
• They cannot be calibrated with high degree of
precision with D.C on account of the effect of
hysteresis in the iron rods or vanes .
MOVING COIL INSTRUMENT – PERMANENT
MAGNET TYPE
Principle :
when a current carrying conductor is placed in
magnetic field it is acted upon by a force which tends
to move it to one side and out of the field. This
movement of coil is used to measure current or
voltage.
Construction
• This instrument consists of a
permanent magnet and a
rectangular coil of many turns
wound on a light aluminium or
copper former inside which is an
iron core
• The sides of the coil are free to
move in the two air gaps between
the poles and core
• To the moving coil spindle is
attached, a pointer is attached to the
spindle to move over a calibrated
scale.
Working
• A magnetic field of sufficient density is produced by
the permanent magnet.
• The moving coil carries the current or a current
proportional to the voltage to be measured.
• Hence, an electromagnetic force is produced which
tends to act on the moving coil and moves it away
from the field.
• This movement makes the spindle move and so the
pointer gives a proportionate deflection
• Deflecting torque : It is directly proportional to the
current or the voltage to be measured. So, the instrument can
be used to measure direct current and dc voltage.
• Control torque
: Spring control.
• Damping torque : Eddy current damping.Damping is
electromagnetic by eddy currents induced in the metal frame
over which the coil is wound. Since the frame moves in an
intense magnetic field, the induced eddy currents are large and
damping is very effective.
The permanent-magnet moving coil (PMMC) type instruments
have the following advantage and disadvantages:
ADVANTAGES
1. They have low power consumption
2. Their scales are uniform and can be designed to extend over and arc of 1700 degree or
so
3. They possess high (torque/weight) ratio.
4. They can be modified what the help o f shunts and resistances to cover a wide range of
currents and voltages.
5. They have no hysteresis loss.
DISADVANTAGES
1. Due to delicate construction and the necessary accurate machining and assembly of
various parts, such instruments are somewhat costlier as compared to moving iron
instruments.
2. Some errors are set in due to the ageing of control springs and the permanent magnets.
MOVING COIL INSTRUMENTS –
DYNAMOMETER TYPE
Principle
An electrodynamic instrument is a moving coil instrument
in which the operating field is produced, not by a
permanent but by another fixed coil. This instrument can
be used either as an ammeter or voltmeter but is
generally used as a wattmeter.
Construction
• Fixed coil (F) is made in two
sections.
• In the space between two,
Moving coil (M) is placed.
• Moving coil is attached to the
spindle to which pointer is
attached.
• The pointer is allowed to move
over a calibrated scale
Working
• The fixed coil and the moving coil carry
currents. Thus, two magnetic fields are
produced.
• Hence, an electromagnetic force tends to act
on the moving coil and makes it move.
• This makes the pointer gives a proportionate
deflection.
Deflecting torque
As voltmeter: The two coils are electrically in series. Deflecting torque is
proportional to square of voltage to be measured. Hence used for
measuring ac and dc voltages.
As ammeter: The two coils are electrically in series. Deflecting torque is
proportional to square of current to be measured. Hence used for
measuring ac and dc currents.
As wattmeter: Fixed coils carry the system current. Moving coil carries a
current proportional to the system voltage. The deflecting torque is
proportional to V ICos
φ i.e. Power to be measured
Control torque
: Spring control.
Damping torque : Air damping.
The Oscilloscope
• The oscilloscope is basically a graphdisplaying device - it draws a graph of an
electrical signal.
• In most applications the graph shows how
signals change over time: the vertical (Y) axis
represents voltage and the horizontal (X) axis
represents time.
• The intensity or brightness of the display is
sometimes called the Z axis.
The graph can give us information about many things
about a signal. Here are a few:
• You can determine the time and voltage values of a
signal.
• You can calculate the frequency of an oscillating
signal.
• You can see the "moving parts" of a circuit
represented by the signal.
• You can tell if a malfunctioning component is
distorting the signal.
• You can find out how much of a signal is direct
current (DC) or alternating current (AC).
• You can tell how much of the signal is noise and
whether the noise is changing with time.
X, Y, and Z Components of a
Displayed Waveform
•
What does an oscilloscope do?
• An oscilloscope is easily the most useful
instrument available for testing circuits
because it allows you to see the signals at
different points in the circuit.
• The best way of investigating an electronic
system is to monitor signals at the input and
output of each system block, checking that
each block is operating as expected and is
correctly linked to the next. With a little
practice, you will be able to find and correct
faults quickly and accurately.
How Does an Oscilloscope Work?
To better understand the oscilloscope controls, we
need to know a little more about how oscilloscopes
display a signal.
Analog oscilloscopes work somewhat differently than
digital oscilloscopes. However, several of the internal
systems are similar.
Analog oscilloscopes are somewhat simpler in
concept and are described first, followed by a
description of digital oscilloscopes.
Analog and Digital
Oscilloscopes
• Oscilloscopes also come in analog and digital types. An analog
oscilloscope works by directly applying a voltage being
measured to an electron beam moving across the oscilloscope
screen. The voltage deflects the beam up and down
proportionally, tracing the waveform on the screen. This gives
an immediate picture of the waveform.
• In contrast, a digital oscilloscope samples the waveform and
uses an analog-to-digital converter (or ADC) to convert the
voltage being measured into digital information. It then uses
this digital information to reconstruct the waveform on the
screen.
Analog Oscilloscopes
• When you connect an oscilloscope probe to a circuit, the
voltage signal travels through the probe to the vertical system
of the oscilloscope. Figure 6 is a simple block diagram that
shows how an analog oscilloscope displays a measured signal
• Depending on how you set the vertical scale (volts/div
control), an attenuator reduces the signal voltage or an
amplifier increases the signal voltage.
• Next, the signal travels directly to the vertical deflection plates
of the cathode ray tube (CRT). Voltage applied to these
deflection plates causes a glowing dot to move. (An electron
beam hitting phosphor inside the CRT creates the glowing
dot.) A positive voltage causes the dot to move up while a
negative voltage causes the dot to move down.
• The signal also travels to the trigger system to start or trigger a
"horizontal sweep." Horizontal sweep is a term referring to the
action of the horizontal system causing the glowing dot to move
across the screen.
• Triggering the horizontal system causes the horizontal time base to
move the glowing dot across the screen from left to right within a
specific time interval.
• Many sweeps in rapid sequence cause the movement of the
glowing dot to blend into a solid line. At higher speeds, the dot
may sweep across the screen up to 500,000 times each second.
• Together, the horizontal sweeping action and the vertical
deflection action traces a graph of the signal on the screen.
• The trigger is necessary to stabilize a repeating signal. It ensures
that the sweep begins at the same point of a repeating signal
Triggering Stabilizes a Repeating
Waveform
Analog Oscilloscope Block Diagram
Analog Oscilloscope Front Panel
Digital Oscilloscopes
• Some of the systems that make up digital
oscilloscopes are the same as those in analog
oscilloscopes; however, digital oscilloscopes contain
additional data processing systems.
• With the added systems, the digital oscilloscope
collects data for the entire waveform and then
displays it.
• When you attach a digital oscilloscope probe to a
circuit, the vertical system adjusts the amplitude of
the signal, just as in the analog oscilloscope.
• Next, the analog-to-digital converter (ADC) in
the acquisition system samples the signal at
discrete points in time and converts the signal's
voltage at these points to digital values called
sample points.
• The horizontal system's sample clock
determines how often the ADC takes a sample.
• The rate at which the clock "ticks" is called the
sample rate and is measured in samples per
second.
• The sample points from the ADC are stored in
memory as waveform points.
• More than one sample point may make up one
waveform point.
• Together, the waveform points make up one
waveform record.
• The number of waveform points used to make a
waveform record is called the record length.
• The trigger system determines the start and stop
points of the record. The display receives these record
points after being stored in memory.
• Depending on the capabilities of your
oscilloscope, additional processing of the
sample points may take place, enhancing the
display.
• Pretrigger may be available, allowing you to
see events before the trigger point.
• Fundamentally, with a digital oscilloscope as
with an analog oscilloscope, you need to adjust
the vertical, horizontal, and trigger settings to
take a measurement.
Digital Oscilloscope Block Diagram
Sampling Methods
• The sampling method tells the digital oscilloscope how to collect sample
points. For slowly changing signals, a digital oscilloscope easily collects
more than enough sample points to construct an accurate picture. However,
for faster signals, (how fast depends on the oscilloscope's maximum sample
rate) the oscilloscope cannot collect enough samples.
• The digital oscilloscope can do two things:
A) It can collect a few sample points of the signal in a single pass (in real-time
sampling mode) and then use interpolation. Interpolation is a processing
technique to estimate what the waveform looks like based on a few points.
B) It can build a picture of the waveform over time, as long as the signal
repeats itself (equivalent-time sampling mode).
Real-time Sampling
Digital Oscilloscope Front Panel
Digital and Analog Oscilloscopes
Display Waveforms
Performance Terms
The terms described in this section may come up in your discussions
about oscilloscope performance. Understanding these terms will help you
evaluate and compare your oscilloscope with other models.
• Bandwidth: The bandwidth specification tells you the frequency range the
oscilloscope accurately measures.
As signal frequency increases, the capability of the oscilloscope to
accurately respond decreases. By convention, the bandwidth tells you the
frequency at which the displayed signal reduces to 70.7% of the applied
sine wave signal. (This 70.7% point is referred to as the "-3 dB point," a
term based on a logarithmic scale.)
• Rise Time : Rise time is another way of describing the useful frequency
range of an oscilloscope. Rise time may be a more appropriate performance
consideration when you expect to measure pulses and steps. An
oscilloscope cannot accurately display pulses with rise times faster than the
specified rise time of the oscilloscope
• Vertical Sensitivity :The vertical sensitivity indicates how
much the vertical amplifier can amplify a weak signal. Vertical
sensitivity is usually given in millivolts (mV) per division. The
smallest voltage a general purpose oscilloscope can detect is
typically about 2 mV per vertical screen division.
• Sweep Speed :For analog oscilloscopes, this specification
indicates how fast the trace can sweep across the screen,
allowing you to see fine details. The fastest sweep speed of an
oscilloscope is usually given in nanoseconds/div.
• Gain Accuracy: The gain accuracy indicates how accurately
the vertical system attenuates or amplifies a signal. This is
usually listed as a percentage error.
• Time Base or Horizontal Accuracy: The time base or
horizontal accuracy indicates how accurately the horizontal
system displays the timing of a signal. This is usually listed as
a percentage error.
• Sample Rate: On digital oscilloscopes, the sampling rate
indicates how many samples per second the ADC (and
therefore the oscilloscope) can acquire. Maximum sample
rates are usually given in megasamples per second (MS/s). The
faster the oscilloscope can sample, the more accurately it can
represent fine details in a fast signal. The minimum sample
rate may also be important if you need to look at slowly
changing signals over long periods of time. Typically, the
sample rate changes with changes made to the sec/div control
to maintain a constant number of waveform points in the
waveform record.
• ADC Resolution (Or Vertical Resolution): The resolution, in bits, of the
ADC (and therefore the digital oscilloscope) indicates how precisely it can
turn input voltages into digital values. Calculation techniques can improve
the effective resolution.
• Record Length : The record length of a digital oscilloscope indicates how
many waveform points the oscilloscope is able to acquire for one waveform
record. Some digital oscilloscopes let you adjust the record length. The
maximum record length depends on the amount of memory in your
oscilloscope. Since the oscilloscope can only store a finite number of
waveform points, there is a trade-off between record detail and record
length. You can acquire either a detailed picture of a signal for a short
period of time (the oscilloscope "fills up" on waveform points quickly) or a
less detailed picture for a longer period of time. Some oscilloscopes let you
add more memory to increase the record length for special applications.
Types of Waves
•
•
•
•
Sine waves
Square and rectangular waves
Triangle and sawtooth waves
Step and pulse shapes
Sine Waves
The sine wave is the fundamental wave shape for several reasons. It has
harmonious mathematical properties - it is the same sine shape you may
have studied in high school trigonometry class.
The voltage in your wall outlet varies as a sine wave. Test signals produced
by the oscillator circuit of a signal generator are often sine waves. Most AC
power sources produce sine waves. (AC stands for alternating current,
although the voltage alternates too. DC stands for direct current, which
means a steady current and voltage, such as a battery produces.)
• The damped sine wave is a special case you may see in a circuit that
oscillates but winds down over time.
Square and Rectangular Waves
• The square wave is another common wave shape. Basically, a
square wave is a voltage that turns on and off (or goes high
and low) at regular intervals. It is a standard wave for testing
amplifiers - good amplifiers increase the amplitude of a square
wave with minimum distortion. Television, radio, and
computer circuitry often use square waves for timing signals.
• The rectangular wave is like the square wave except that the
high and low time intervals are not of equal length. It is
particularly important when analyzing digital circuitry.
Sawtooth and Triangle Waves
• Sawtooth and Triangle waves result from
circuits designed to control voltages linearly,
such as the horizontal sweep of an analog
oscilloscope or the raster scan of a television.
The transitions between voltage levels of these
waves change at a constant rate. These
transitions are called ramps.
Step and Pulse Shapes
• Signals such as steps and pulses that only occur once are
called single-shot or transient signals. The step indicates a
sudden change in voltage, like what you would see if you
turned on a power switch. The pulse indicates what you would
see if you turned a power switch on and then off again. It
might represent one bit of information traveling through a
computer circuit or it might be a glitch (a defect) in a circuit.
• A collection of pulses travelling together creates a pulse train.
Digital components in a computer communicate with each
other using pulses. Pulses are also common in x-ray and
communications equipment.
Waveform Measurements
• Frequency and Period : If a signal repeats, it has a frequency. The
frequency is measured in Hertz (Hz) and equals the number of times the
signal repeats itself in one second (the cycles per second). A repeating
signal also has a period - this is the amount of time it takes the signal to
complete one cycle. Period and frequency are reciprocals of each other, so
that 1/period equals the frequency and 1/frequency equals the period. So,
for example, the sine wave in Figure 7 has a frequency of 3 Hz and a period
of 1/3 second.
• Voltage : Voltage is the amount of electric potential (a kind of signal
strength) between two points in a circuit. Usually one of these points is
ground (zero volts) but not always - you may want to measure the voltage
from the maximum peak to the minimum peak of a waveform, referred to at
the peak-to-peak voltage. The word amplitude commonly refers to the
maximum voltage of a signal measured from ground or zero volts. The
waveform shown in Figure 8 has an amplitude of one volt and a peak-topeak voltage of two volts.
• PHASE: Phase is best explained by looking at a sine
wave. Sine waves are based on circular motion and a
circle has 360 degrees. One cycle of a sine wave has
360 degrees, as shown in Figure 8. Using degrees,
you can refer to the phase angle of a sine wave when
you want to describe how much of the period has
elapsed.
•
Phase shift describes the difference in timing between
two otherwise similar signals. In Figure 9, the
waveform labeled "current" is said to be 905 out of
phase with the waveform labeled "voltage," since the
waves reach similar points in their cycles exactly 1/4
of a cycle apart (360 degrees/4 = 90 degrees). Phase
shifts are common in electronics.
Applications of CRO
• Oscilloscopes are used by everyone from television repair
technicians to physicists. They are indispensable for anyone
designing or repairing electronic equipment.
• The usefulness of an oscilloscope is not limited to the world of
electronics. With the proper transducer, an oscilloscope can
measure all kinds of phenomena. A transducer is a device that
creates an electrical signal in response to physical stimuli, such
as sound, mechanical stress, pressure, light, or heat. For
example, a microphone is a transducer.
• An automotive engineer uses an oscilloscope to measure
engine vibrations. A medical researcher uses an oscilloscope to
measure brain waves. The possibilities are endless.
Scientific Data Gathered by an
Oscilloscope