An oscilloscope (scope) is an electronic instrument that displays a voltage input on a screen as a function of time. It is used to display and measure repetitive waveforms or transient signals.
Picture of an oscilloscope
Common oscilloscope operating parameters
- > 1 megaohm
- A high input impedance is used to prevent the scope from affecting the circuit being tested.
- 50 ohms
- Used to match the 50 ohm output impedance of fast amplifiers and other devices.
- Straight input connection, the screen trace shows both dc and ac components of the input signal.
- Places a capacitor in series with the signal input to capacitively couple only the ac signal into the scope. Useful for measuring small ac signals on a large dc offset.
- Useful for finding the zero volt level on the screen.
- signal input channel (e.g. CH1)
- Triggers at some voltage on the input signal. Usually used for repetitive waveforms.
- The ac power line, triggers the scope at 60 Hz.
- An external trigger that is synchronizes the oscilloscope to the signal being displayed. Usually used for transient events.
trigger level and slope
- The adjustable voltage level at which the scope triggers when the trigger input crosses this value.
- The slope of the trigger can be set for either the rising or falling edge.
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Copyright © 1996 by Brian M. Tissue