We’re checking out the latest Oscilloscope from our friends over at Jaycar. Is it a worthy successor to its older brother?
An essential part of any enthusiast maker's kit is the humble oscilloscope, so it’s important to pick one suitable for your needs. For those who are unfamiliar or need a refresher, an oscilloscope is effectively a very high-speed voltmeter. They’re purpose-built for inspecting signals down to the nanosecond. They can measure, analyse and decode all sorts of electronics, helping solve both simple and complex problems in your circuits.
This month, the new QC1938 Oscilloscope from Jaycar has landed on our desks, so we’re checking out what’s new and improved over the older QC1936 scope. While the two model numbers are almost identical, there is a considerable difference to the overall functionality and physical appearance.
The first thing immediately obvious is the new facelift compared to the old scope. The older scope had a two-tone black and white enclosure, while the new one sports a slightly smaller all-grey enclosure.
The layout of the front panel buttons has also changed, spacing out the buttons across the right side of the unit. It’s a more ergonomic design than its predecessor and has a layout that echoes many other big-name oscilloscopes. All buttons are soft and rubberised, and ones related to channel selection, run-mode and waveform generation are also illuminated.
USB-A and USB-B ports are present, on the front and back of the unit respectively. The USB-A port can be used for saving and recalling waveforms, as well as saving images to a USB flash drive. The USB-B port can be connected to any host computer and controlled via standard Keysight software or SCPI, which we utilised a lot in this month’s Classroom!
As far as we can tell, this scope is based on the Hantek DSO2000, considering that the software, button layout and general design is almost identical. In our experience, Hantek makes good quality equipment so we are confident that the QC1938 will follow suit.
On the left side is a 800px x 480px 7” LCD, which is vivid and easy to read. While the older model used the same type of screen, the new one has an arguably better interface. It’s better laid out, more modern and has plenty of space for waveforms.
The previous QC1936 scope used five BNC connectors, two of which were input channels and the rest related to triggering and wave generation. The new scope uses only three BNCs, which frees up more space on the front panel in exchange for slightly less output features if you have specific requirements of the triggering system.
The whole unit isn’t as hefty as other scopes but still feels solid enough, and should be able to hold up to the bashing and crashing of a busy workshop.
Both the new and previous oscilloscopes from Jaycar have a very capable 100MHz bandwidth, which is more than enough for most makers. The biggest change in terms of raw numbers is the memory depth the new unit brings - 8 million to be exact. Comparing to the old scope’s 40k memory points, the new scope is an improvement of 200x!
An oscilloscope's memory is used for storing data points as they are recorded from the input. A larger memory depth allows a higher sampling rate to be used, or acquisition time to be longer. While this won’t be a critical matter for signals related to simple Arduino communications, for high-frequency waveforms or circuits that have complex functionality in small durations of time, it can be a huge help.
This scope also has inbuilt decoding of most common protocols that maker hardware runs on, including I2C, CAN, SPI and UART. We didn’t get an opportunity to fully test the decoding features, but the menus are fully-featured as much as higher-end oscilloscopes, which is impressive!
The Math Menu allows the four mathematical operations (addition, subtraction, division and multiplication) to be completed on the two channels, and also features Fast Fourier Transform for analysing the component frequencies of waves in real-time. We’d like to see more mathematical operations, such as differentiation, integration and boolean operations, but in any case, these options are adequate.
Along with other tools like soldering irons and power supplies, oscilloscopes are tools that will be used frequently in a busy workshop. If it’s easy to use, it will make every maker’s life easier.
The rotary encoders on the front panel feel on the cheaper side, but are detented and provide a tactile click when pressed. On some scopes, pushing in the vertical scale knobs will switch between fine and coarse adjustment, but on this scope, you’ll need to go into the channel menu to change it.
We really liked that each vertical channel has its own position and scale knobs. Some scopes, especially with more than two channels, use just one knob for each, and use the last channel selected to guess which channel to modify.
Some of the UI is a little slow, but it’s more than usable and to be expected for an oscilloscope at this price point. The internal processor sometimes struggles to keep up with the data. Although it wasn’t annoying, sometimes it took a bit of time for the scope to rescale the input signal when changing vertical or horizontal scales.
There are also a few other cool features that make this scope outshine its entry-level status. It’s possible to enable a digital voltmeter and frequency counter on both channels, which is super handy for monitoring the voltage of a signal without adding separate sets of probes with a dedicated multimeter.
This scope also comes with an inbuilt waveform generator which is surprisingly capable. For those new to the world of electronics equipment, a waveform generator can generate a custom signal with parameters set by the user. For example, if a 4V square wave centred around -1V was desired, it can be generated on the waveform generator output.
It also has a variety of arbitrary waveforms that can be modified via the included software. While we didn’t experiment with using the software, it’s capable of generating all sorts of custom mathematical functions.
It can also generate AM and FM modulated waves, and output a trigger signal if you wish to run other circuits while your oscilloscope is capturing data.
The burst mode has a dedicated button on the front panel, which outputs a predetermined number of waves from the function generator output. This would be really handy if you want to test voltage transients or spikes and need to analyse how your circuit responds to it.
There are a few points of criticism about this new oscilloscope that could be thrown around, however, we think it’s important to think about the price point that the scope sits at. It’s very competitive in terms of features, and its unique, low-cost position is something that many will find interesting.
The Rigol DS1054Z, a very popular entry-level oscilloscope option for many enthusiasts, is priced noticeably higher than this scope, but with features such as increased memory depth (12M) and four channels. Scopes like this are the QC1938’s nearest competitor, and we think it stacks up quite well considering its price point.
There are, of course, literally hundreds of features available in the higher-end oscilloscopes from Keysight, Agilent and so forth. When it comes to more advanced applications such as protocol decoding and math functions, sure, a decent scope is useful. However, even on our fancy scopes here in the office, 95% of the time we’re only using basic features.
We often use oscilloscopes as basic voltmeters when it comes to multi-channel measurement, so having a plethora of features isn’t always necessary. So, a better question is to ask - are some extra high-end features worth a premium price point?
That’s precisely why we were happy with the QC1938, as it offers everything a competitive scope should have (and more). Doing any Arduino work with this scope will be a breeze, and the vast majority of makers won’t run into its minor limitations interfacing with most electronics projects we feature in DIYODE.
We’re pleased with the quality of the QC1938 and would recommend it to any beginner looking for a
one-size-fits-all oscilloscope. It’s clearly designed as an entry-level scope, but its features impressed us and they would feel right at home in a much more expensive scope. Overall, it’s a very capable unit that improves on various features of its predecessor and sprinkles in a few extra for good measure!
The 100MHz Digital Oscilloscope with 8M Memory Depth is available from Jaycar
- 100MHz Digital Oscilloscope QC1938