OSCILLOSCOPES FOR NEOPHYTES

Chances are you’ve seen an oscilloscope before, even if you weren’t aware of it at the time. These boxy pieces of testing equipment feature display screens with a grid pattern — known as a graticule with each square therein called a division — that is used to measure signals input into these devices. The oscilloscopes front panel has a number of control buttons and knobs as well as several input connectors.

Capable of identifying and displaying signal voltages, digital storage oscilloscopes and their analog brethren enable technicians to examine the displayed data for testing and troubleshooting electronic equipment. Very basic oscilloscopes have a horizontal trace line on the graticule display that goes from left to right across the screen and this trace allows you to measure voltage over time; older data regarding voltage will be displayed on the left side of the screen while newer data is to be found on the right side.

These simplistic oscilloscopes are adjusted using the timebase control which determines the speed at which the trace is displayed (measured in seconds per division). The oscilloscope’s vertical control indicates the trace’s vertical deflection’s scale — i.e., how far the trace moves up or down across the graticule (measure in volts per division). Measuring the trace can be difficult because the timebase may not be precise and the input signal(s) might be unstable.

Because of the difficulty of measuring the trace, newer oscilloscopes have a saddle function that enables the oscilloscope to stop just before the trace is terminated on the right side of the graticule. These types of oscilloscopes can be triggered to begin a new trace if an anticipated event occurs — e.g., when a waveform reaches a predetermined threshold voltage. This saddle function helps prevent the typical horizontal drift that older oscilloscopes suffer from as a result of their trace.

Although they are still sometimes used today, the older analog oscilloscopes were pretty simple measuring instruments which have been made obsolete with the invention of modern digital storage oscilloscopes, including handheld oscilloscopes and PC-based USB oscilloscopes that have impressive specifications and incredible accuracy.

George

George Leger has a Masters in Electrical Engineering from Stanford University, worked in private industry pioneering surface-mount technology and in government research labs for twenty years, published several papers on surface-mount technology, co-authored papers published in national symposiums on accelerator technology, was past president of SMTA and an adjunct professor at the community college level, holds a patent, and is a certified microchip design partner, serving as a consultant to many companies developing electronic circuits.

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