Introduction to Oscilloscopes Nick Carter 3/19/2016

What’s in a name? What is an Oscilloscope Anyone speak Greek or Latin? Scientists use Greek and Latin words to describe their inventions. Understanding a bit of older languages can help figuring out things in science (and English too). “Oscillo” from Latin “swing” Think of a pendulum. A repeating movement of something “Scope” from Latin and Greek - Think about looking at things – other words like Tele-scope – “Tele” – far off “Scope” – watching So it lets us look at repeating electrical signals

It has a picture of something.

Say What? What is this? It is a graph of voltage against time. An Oscilloscope repeatedly makes a dot of light cross a display from left to right…. This is called the “X” direction – representing time You can make your own on paper. Move a pencil up and down and pull the paper under it. It has a input connection where you can put an electrical signal that will move the dot up and down depending on the size of the signal This is called the “Y” direction – representing the signal Voltage It has a way to detect when the repeating signal happens so that each time the next signal repeat gets started it is displayed on top of the last one. That way each signal repeat is redisplayed identically. This is called “triggering” - starting the dot moving from the left Special connection cables called “Probes” are used to connect to the signal source. They are designed not to change the signal or the function of the equipment that is making it.

Looking at the Oscilloscope Getting a good picture The display has a grid that is marked in centimeters that you can measure the signal with You can adjust the scaling of the signal and the time to get a convenient picture that makes sense for your purpose and measurement You can adjust the signal up and down and left and right to be where you want it on the grid You can adjust the trigger so that the signal wave shape display is where you want it --  Voltage  +

A Really Good Old Oscilloscope Tektronix Type 454 Time Controls (Horizontal) Display Controls Input Controls (Vertical) Input Selector 1 or 2 or both Trigger Controls Voltage Input 2 Voltage Input 1

Similar Screen Example Hospital monitors with heartbeat

Online Resources This virtual one is nice, and it is a very nice set of teaching aids : http://www.educationscotland.gov.uk/resources/s/sound/oscilloscope.asp?strReferringChannel=resources&strReferringPageID=tcm:4-248295-64   And an online virtual oscilloscope… https://academo.org/demos/virtual-oscilloscope/