- Oscilloscopes display the properties of electrical signals as they change over time
- Most oscilloscopes offer a number of tools or options to measure electrical signals
- Proper triggering helps to fix the waveform in one spot on the display
An oscilloscope displays electrical signals as they change over time. Understanding the operation of an oscilloscope allows for in-depth examination of a circuit and/or electrical components. Oscilloscopes measure noise levels, cycle frequency, and other electrical specifications of a circuit. This guide covers the basic use and features of an oscilloscope.
Quick Start Guide
After powering the oscilloscope, connect or locate an attached oscilloscope probe [Figure 1]. The probes typically twist on and off of the oscilloscope and can be replaced or exchanged. Each probe should have a spring-loaded cap that allows the oscilloscope to be clipped onto wires or pins. This end cap can be removed to expose a pointed tip for testing finer leads and vias. The last element of the probe is typically a gator clip to connect to the ground terminal of the tested device.
Once the scope probes are properly connected, the oscilloscope displays the observed waveform information. Oscilloscopes typically designate both vertical and horizontal controls. Depending on the vertical and horizontal scaling, you may need to locate this waveform. The Volts/Div dial controls the vertical scaling, and the Sec/Div dial controls the horizontal scaling. Each set of controls should also have a positioning knob to help locate and align waveforms.
With the waveform in the view window, setting an appropriate trigger point allows continuous and easy observation of the waveform. Without proper triggering, the waveform will move across the screen and may not provide a clear picture. Triggering helps to hold a waveform stable on the screen and displays the signals of interest. For basic triggering, select a rising or falling edge as the trigger method and adjust the trigger level to sit below the peak or above the bottom of the waveform for the two respective trigger methods.
Clearly displayed waveforms in the view window allow you to capture signal measurements. As well as having designated vertical and horizontal controls, many oscilloscopes have a series of menus for capturing information about the waveform. Measure and cursor menus help to take measurements of voltage and frequency. The acquire menu will let you store the displayed waveform for future comparison. These additional controls should enable you to capture the information you need.
|Position||Position is used to shift the waveform higher or lower on the screen|
|Volts/Div||Volts/Div adjusts the vertical scaling|
|Coupling||Coupling allows you select if the probe is being connected to an AC or DC power source|
|BW Limit||Restricts the frequencies that you are observing to cut down on noise (higher restrictions may remove valuable information along with noise)|
|Volts/Div||Adjusts how much turning the Volts/Div knob does|
|Probe||Adjusts this setting to match the attenuation setting on the probe|
|Invert||Inverts the reported waveform|
|Position||Position is used to shift the waveform left or right on the screen|
|Sec/Div||Sec/Div adjusts the horizontal scaling|
|Type||Edge is basic and it looks for a rising or falling edge at a specific amplitude|
|Source||Allows selecting what source is monitored for the trigger|
|Slope||Allows you to determine if you are looking for a rising or falling slope to trigger the oscilloscope|
|Level||Sets the height of the trigger voltage level|
|Set to 50%||Places the trigger between the peaks of the signal|
|Measure||Provides an assortment of measurement options such as measuring average voltage or period length|
|Acquire||Allows you to save the waveform in the oscilloscope’s memory|
|Cursor||Allows you to place cursors on the oscilloscope screen to mark key features which can be used to measure time and voltage|
|Single Seq.||Allows the oscilloscope to take one reading, display the reading, and stop|
|Run/Stop||Allows continuous display reading and updating|