An oscilloscope is a valuable piece of lab equipment for engineers, and many companies—including Tektronix, Fluke and Instek - offer many options when trying to find the right oscilloscope. While the purposes and value of oscilloscopes will not be discussed in this article, ways of finding the right oscilloscope will be examined. Whether purchasing a new, used or surplus oscilloscope, the following information will help professionals and hobbyists choose the oscilloscope they need. See this entire review to find out more.
Things to Look For in an Oscilloscope
No matter where an oscilloscope is purchased or whether the model is new or used, take into consideration the following information.
Analog Vs Digital
If possible, choose a digital oscilloscope over an analog model. Those allow for digital storage of recorded information and are generally more accurate. It’s also much easier to take measurements with digital oscilloscopes. Analog models can usually be purchased very inexpensively used, but digital models will produce better measurements and are dropping in price.
Accuracy and Calibration
Using a major brand name lab scope such as Tektronix, Fluke or Instek will have far more accuracy than the average hobbyist needs. Since oscilloscopes are used to look at waveforms and relationships, precise accuracy is generally unnecessary for non-professional applications. However, choosing an oscilloscope with high accuracy is a must when using the equipment for professional purposes or high-level experiments where precision is absolutely necessary.
Calibration can be tricky when purchasing used oscilloscopes, but a basic calibration of the voltage scales is relatively simple. Advanced, full calibrations can be tricky and time-consuming, but by purchasing from a reputable vendor, one can often avoid needing to fully re-calibrate a used oscilloscope.
The Number of Channels
Generally speaking, do not purchase a single channel oscilloscope. Oscilloscopes with two or more channels are widely available and often worth a little extra cost. Dual channel equipment is necessary for many types of measurements, and it’s always better to invest a little more up front instead of having to purchase another machine down the line when it comes to lab equipment.
Measurement Ranges
Similar to accuracy, most of the name brand oscilloscopes will have sufficient measurement ranges for most applications. Of course, there are exceptions, and one should examine what measurement ranges are necessary for particular experiments when choosing equipment.
Bandwidth should be taken into consideration. An oscilloscope should have a bandwidth of at least 100mhz. If possible, choose a model with at least 250mhz of bandwidth. For general purpose use, 250mhz is about as high as anyone would need. Like measurement ranges, though, one should examine specific needs when determining the actual amount of bandwidth necessary. Often, the “calibration” bandwidth (for example, 200mhz) is lower than the usable bandwidth, meaning a machine can be used for general testing and troubleshooting for much higher frequencies at the cost of some accuracy.
Other Features to Include
While some oscilloscopes may not come with these features, it’s prudent to make sure a lab’s oscilloscope has delayed sweep, triggered sweep, horizontal input and probes. Delayed sweep is very useful for troubleshooting digital circuits and finding glitches. Even if this feature is only used occasionally, it is still worth investing in when choosing an oscilloscope.
Triggered sweep comes with almost all name band oscilloscopes, but a point should still be made to choose equipment that has this feature. Some experimenters will want horizontal (Y-axis) input, so if this is important it should be looked for. Finally, avoid purchasing used probes. Probes go bad regularly and often need to be replaced. It is generally not necessary to choose probes made by the same manufacturer as the oscilloscope.
Oscilloscope Brands Compared
With an understanding of what features an oscilloscope should have, one might wonder how oscilloscope brands rank with each other. Like any type of equipment, some brands are better than others. Read on to see which of the major brands would work best.
Fluke manufactures some of the best handheld units.
Fluke
Fluke is considered to be a brand leader in the field of handheld oscilloscopes, but Fluke oscilloscopes can also be some of the most expensive options. Generally, Fluke models comes with lots of features and are built to survive in rugged, harsh environmental conditions. A Fluke oscilloscope could be a good choice for professionals needing to take measurements in the field.
Tektronix
Tektronix is the oldest name in the oscilloscope industry, and for good reason. Tektronix sets the industry standard with their equipment and often leads ahead of other companies in bandwidth, noise performance, effective number of bits and in sampling rates. Many engineers also prefer the interface Tektronix uses for its oscilloscopes. Tektronix oscilloscopes cost a little more than some other brands, but they are reliable and usually state-of-the-art when purchased new.
Instek
Instek oscilloscopes tend to be less expensive than other brands. Many customers are satisfied with using Instek models for their needs. However, some customers have experienced problems dealing with Instek’s customer service. If all that is needed is a basic oscilloscope with standard features at a low price, then Instek may be the right choice.
My Opinion on Brand Choice
Whichever oscilloscope is chosen, make sure the actual model of oscilloscope has the features explained above. As previously mentioned, it’s better to invest a little more when purchasing equipment than to have to upgrade sonn after a purchase because the first oscilloscope can’t perform needed measurements.
Conclusion
Choosing the right oscilloscope for a professional or amateur lab doesn’t have to be hard. If possible, choose a digital storage oscilloscope with a good sample rate (much higher than 100mhz). Make sure it has features like delayed sweep and can give information in real time. Purchase a model that can measure accurately at a higher frequency to make sure proper measurements can be taken. Above everything else, always remember to purchase an oscilloscope with as many features as possible so that an expensive upgrade isn’t needed shortly after acquiring the first model.
With so many options and brands to choose from, finding the right oscilloscope is simply a matter of taking the time to do a little research. Talk to a customer service representative from a reputable laboratory electronics dealer to learn more.
