External trigger. This is not used often but is sometimes very useful. The trigger controls let you stabilise repeating waveforms and capture single-shot waveforms. The trigger makes repeating waveforms appear static on the oscilloscope display.
Display size. Display size always matters as we see signal waveforms on the oscilloscope’s screen. A bigger screen display is always more comfortable to watch and work with. There are traditional cathode ray tubes, thin-film-transistor liquid-crystal displays with touchscreen display, flexible display and so on.
Form factor. Oscilloscopes may be divided into three categories depending on size and shape: benchtop, handheld and PC based.
A benchtop oscilloscope is aimed at having the highest performance. Almost all functionalities are available in this category. Handheld is portable and hence advantageous for the user on the move, but display quality and performance may be poor as compared to benchtop.
A PC based oscilloscope is becoming popular because PCs and laptops are easily available at home or workplace. You just need a portable external hardware or a dedicated add-on card in your PC along with suitable software.
Wireless supported. Wireless oscilloscopes support Bluetooth and Wi-Fi interface. The oscilloscope uses Wi-Fi module to create its own WLAN hotspot. Measurements can be done using the Web browser on a notebook, tablet or mobile phone.
With wireless, the PC becomes a virtual oscilloscope and can be used in special situations such as monitoring the signal while on the move or life-risky environment like in nuclear stations. But most wireless oscilloscopes have limited bandwidth.
IoT supported. Scopes having built-in wireless LAN module or Wi-Fi module act as hotspots. Some oscilloscopes have dedicated Ethernet ports for connecting to the Internet. Measurements can be monitored remotely using the Web browser on tablets, smartphones or PCs. The Internet of Things (IoT) capability on the scope allows measurements on high-voltage environments and brings safety to users.
Industrial automation, education management, remote test and measurement and some other functions need IoT oscilloscopes.
Technical specifications of some budget-friendly oscilloscopes are listed in Table II.
New trends in Oscilloscopes
In recent years, we have seen many changes in budget-friendly oscilloscopes. We see many innovations with added features in today’s oscilloscope like better performances including higher capture rate and CPU performance, features such as smart trigger and decoding, and mixed-signal oscilloscopes and arbitrary waveform generators.
Technological advancement in analogue-to-digital converters has resulted in high vertical resolution scopes that give better measurement accuracy.
Apart from wireless and IoT features, the latest scopes are enhanced with logic analysers, spectrum analysers, digital voltmeters, protocol analysers, counters and so on.
In the future we could see smarter and virtual oscilloscopes with even more features at much lower cost.
To conclude, if you are planning to buy a budget-friendly oscilloscope, first check your requirement, search the Internet for options and see if you can find a value-for-money oscilloscope. But keep in mind that you should never compromise on bandwidth, signal capture rate and display.
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Sani Theo is senior assistant editor – tech at EFY