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Explains what an oscilloscope is and how one is used.

What is an oscilloscope?

An oscilloscope is a device that measures and displays voltages as a time versus voltage graph. The voltage difference between the positive and negative probe leads is measured, buffered, and displayed on the screen as a continuous curve.Because the quality of the scope affects how finely it can resolve changes in time and voltage, very sensitive or small signals may not be measurable with all oscilloscopes.For most educational purposes, however, an average oscilloscope will display the signal well enough.

Oscilloscopes are generally used to see if a circuit is performing as expected, but oscilloscopes are also useful for comparing different signals to each other.Comparisons and absolute measurements are made by comparing the signal to the graph on the display.

Oscilloscope controls

The most common oscilloscope controls are for amplitude, frequency, triggering, and signal comparison.

The amplitude adjustment of an oscilloscope controls how tall a given voltage will appear on the screen. Usually the screen will be marked off with horizontal lines to indicate the signal's voltage.The absolute voltage per horizontal line is adjustable. Thus, if the amplitude is set to 1V/ then each block a signal is tall is 1 V.The purpose of this adjustment is that you can see a very large or a very small signal on the same screen.

The time adjustment of an oscilloscope is how much time will a certain distance across the screen represent. The vertical lines most oscilloscopes have are the standard distanceand the knob or screen indicator will describe how time that distance represents. The purpose of this adjustment is to be able to see a very quickly changing or a slowly changing signal on the same screen.

Triggering refers to the means by which the oscilloscope selects the exact moment to display on the screen. Because electrical signals often change far faster than a human being could observe them, it is necessary to onlydisplay a small sampling of the signal. If a signal has a repeating pattern, then the pattern will be repeatedly shown on the screen so that it can be viewed continuously.If the signal does not have a regular pattern then the oscilloscope will have trouble choosing the best moment to refresh the display. In this case, you will need to set up a trigger so that the oscilloscope can freeze the screen at the right time.Trigger controls allow for conditions such as an upward edge of a signal, a voltage glitch, or a voltage threshold. Trigger controls can also allow for the display refresh to occur after a time delay from the time of the trigger event.You should adjust thee triggering of an oscilloscope if the signal seems to be sliding left and right on the display or changing too fast to be seen.

Because many oscilloscopes allow multiple signals to be compared at the same time, it is necessary to have controls to handle the display of these signals. The most basic control is the ability to turn off the channels that are not in use to avoid useless cluttering of the display screen.Oscilloscopes also allow for two different channels to be compared by displaying the additive difference between them instead of the signals individually. Usually different signals can also be displayed with different amplitude adjustments, but they require the same frequency adjustment.Finally, if special triggering conditions are used, the trigger system will ask for which channel should trigger the display.

Hazards to avoid

Triggering is probably the trickiest skill to acquire. Generally, adjusting the voltage level for the default trigger will fix most triggering problems on analog signals.For more complicated observations, the most useful tool in triggering is a time delay. While exact moment of the signal that is interesting to you may not be easy to trigger on,often this moment occurs at a fixed time offset from an event that is easy to trigger on. Try finding a signal transition or voltage threshold that stabilizes the display,then adjusting the time delay to observe your signal.

It is important to ensure that both probes the positive and negative leads of the probe are attached to the device. Usually the negative lead can attach to the ground plane of the device,

Oscilloscope probes must be attached to the signal being measured and to the ground plane of the circuit too.Noise is introduced if both probes are not properly attached to the device.

It is also important to note that the probe itself has a 1M ohm resistance. This means that from most digital circuits, the probe will not draw any significant power.However if you are trying to measure voltage from a node between two 10M ohm resistors, it would drop the voltage by about half! The lesson is that you will sometimes need to be aware of how the probe affects what you are measuring. Finally the capacitance and inductance of the probe itself can affect finely tuned analog signals.Very high speed signals (approaching 100MHz) can be very difficult to measure with an oscilloscope.

Questions & Answers

where we get a research paper on Nano chemistry....?
Maira Reply
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
yes that's correct
I think
Nasa has use it in the 60's, copper as water purification in the moon travel.
nanocopper obvius
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
how nano science is used for hydrophobicity
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
what is differents between GO and RGO?
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
analytical skills graphene is prepared to kill any type viruses .
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Microcontroller and embedded systems laboratory. OpenStax CNX. Feb 11, 2006 Download for free at http://cnx.org/content/col10215/1.29
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