https://community.element14.com/technologies/test-and-measurement/The electronic test and measurement group is intended to prove information on electronic test and measurement equipment, including thermal imaging technology, and also answer any questions you may have.en-USTelligent Community 12https://community.element14.com/technologies/test-and-measurement/b/blog/posts/portable-multimeter---sanwa-pm-300Sun, 28 Jun 2026 15:44:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:0881fbb1-2c8f-4e61-a535-3374f47f3966kk99{gallery}Sanwa PM300 A few years ago I looked for a replacement for my portable multimeter, the Appa iMeter 5, for which I was not fully satisfied. I have found a Sanwa PM300. I have been using it till now, and I am very happy with it. The quality of build is better in comparison to the Appa, it has a really good case. The test probes TL-39T are also very good and have removable test pin covers, which reduce the unshielded area of the pin. Additionally, it supports True TrueRMS on ACV. The only drawback is the lack of the current measurement, but it was really limited in the case of Appa. Below there is specification of Sanwa PM300: Here is a more detailed specification from the user manual: The specification as for a multimeter that can fit in the pocket is reasonable. I have performed some tests to show how it behaves in real usage. The first test was to check DCV with usage of the AD584K voltage reference. Below the results: {gallery}DCV test Voltage reference AD584K Measurement of 2.5 V Measurement of 5.0 V Measurement of 7.5 V Measurement of 10.0 V The next test was related to the measurement of precision resistors: one of 0.005% and the rest of 0.1%. Below there are results: {gallery}Resistance test Measurement of Vishay S102CT 1 kOhm 0.005% 2ppm Measurement of Vishay 10 kOhm 0.1% 25ppm Measurement of 1 MOhm 0.1 % Measurement of 150 Ohm 0.1% Measurement of 15.1 Ohm 0.1% I have also performed a quick check of some diodes. Below are results: {gallery}Diode test Measurement of 1N5817 Measurement of BAV18 I have also checked the capability of measurement of capacitors. Below there are results: {gallery}Capacitor test Measurement of 470 uF 16 V Measurement of 47 uF 35 V Measurement of 470 nF 63 V Measurement of 33 nF 250 V Measurement of 2.2 nF 400 V The last test was for ACV and frequency. For that purpose, I have used the waveform generator built in the Analog Discovery 3. Below there are results: {gallery}ACV and frequency test Measurement of sinus 1 kHz 1 Vpp Measurement of sinus 1 kHz 1 Vpp Measurement of sinus 100 kHz 1 Vpp Measurement of sinus 50 kHz 1 Vpp Measurement of sinus 50 Hz 5V pp Here is check how ACV measurements behave in the case of a frequency change of 1 Vpp sinus signal from 50 Hz to 5 kHz. Below are the results: {gallery}ACV test Measurement of sinus 50 Hz 1 Vpp Measurement of sinus 100 Hz 1 Vpp Measurement of sinus 200 Hz 1 Vpp Measurement of sinus 500 Hz 1 Vpp Measurement of sinus 1 kHz 1 Vpp Measurement of sinus 2 kHz 1 Vpp Measurement of sinus 5 kHz 1 Vpp The continuity check is quite responsive. Additionally, it is nice that it uses very low voltage at open, only 1.0 V. Based on results, they are in the range of provided specification. Probably the things that could be nice to see in the next version, if there is one, will be a backlight and the possibility of measurement of current even in a narrow range. I saw on eBay the version PM300BT, which is probably dedicated to the Japanese market, which excepts standard PM300 features, and has support for Bluetooth for remote measurements via a dedicated application.PM300multimetersanwahttps://community.element14.com/technologies/test-and-measurement/b/blog/posts/gdm-8341-trace-capabilities-reviewFri, 26 Jun 2026 15:40:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:c521abad-42e7-4861-b6fb-2e8fda954a7aobonesBack in March, I was flabbergasted to be chosen as the grand prize winner for the Fun and Games competition I mean, I was participating for the fun of it, thinking to myself "heck, if I reach second place, that'll be a good occasion to replace my aging soldering station by one with a hot air output, and if I'm a finisher, the fume extractor would be a very nice addition to my setup". Last time, my choice was easy, as I did not have an oscilloscope on my desk, but now I had to think about it a bit more which lead to me asking a question about the usefulness of DMMs. All the good answers I received confirmed my choice and after a few days, with the help of E14Alice, I received the GDM-8341 from GW INSTEK. Its look is a bit vintage, but I don’t mind at all, I really appreciate the VFD displays, they have this “sturdy” feeling that I sometimes miss in LCD based approaches. It took me a while to find a proper place to have it installed in my home lab, but now that it’s settled, my first use was to try logging a “slow changing” voltage that I’m seeing when I power up one of my bench top power supply. As you will notice on the video, the two embedded meters are starting from a very high value before settling to the programmed value. https://youtu.be/fSK3N4F_FNA What I was wondering is that if this is a meter module artifact or if the output voltage is indeed overshooting for numerous seconds. As the DMM is provided with a device USB port (type B), it can be connected to a computer that would “talk” to it and get measurements. The manufacturer’s page gives USB Driver and LabView integration, so I thought this would be the perfect occasion to get introduced to LabView that I have seen mentioned around here quite a few times. The goal was to setup the DMM, read values in a loop and post those values into my InfluxDB instance as they come along. I figured this would be a way to exercise my Cursor AI licence and sure enough, it was able to provide me with a plan of action in order to achieve this. Sadly, as LabView files are in binary format, all I received was a “click through” plan of actions with almost every time a choice of possible ways to do things but without any clear recommendation. Even worse, the mentioned menus or buttons most often did not exist in my 2016 Q1 version and even after strongly insisting, it did not provide me with entirely valid instructions. This is most likely related to the delay between training and inferring which can be years. What I find most annoying is that despite telling it I was a perfect noob at this, it failed to explain LabView’s base concepts, the most important one being that everything runs at the same time (on every system tick?), even if the “boxes” are connected. This is perfectly counter intuitive to people like me with a developer background. In the end, I got a set of VI files, with a “master” one that links to the others in what I find a very convoluted way for something that I believe has to be quite simple: A seasoned LabView user would most likely have done things in a simpler or clearer way, but at least I now have values in InfluxDB and can display them in a dashboard like this: The value does not appear to overshoot the programmed value, but it did not feel right that the graph is so “jaggy” with this broken lines aspect. As it turns out, the issue was not with the reading frequency in the LV project but just with the way InfluxDB displays values in a dashboard. Basically, it always “groups” values in bins and uses the aggregation value of each bin as the point in the graphic. As you may have noticed at the top right, this is the “window period” and in the above case, its length is 167ms, automatically computed according to some heuristics that I have no idea about. But this is configurable in the dashboard and with a setting of 1ms, it gives this smoother image: Still no sign of overshoot which is quite reassuring. And for good measure, I fired-up the oscilloscope to better observe the on-ramp which gave this: Well, with more than 600ms rise time, it’s no surprise there is no overshoot, the logic inside the power supply has more than enough time to properly sample its output. With all this, I should be satisfied but LabView still seems like a bazooka to splat a fly, and I don’t really like depending on a software whose usage rights have seen recent tightening, giving a feeling that what happened to VMWare could happen here as well. Furthermore, it still feels mostly foreign to me, and I must admit that using a LLM to “help” build this did not give me any time to actually learn anything of value. Yet another case of fast reward but null long-term return on investment. So, I went back to Cursor and asked it to create a C# application within VSCode, a language and environment that I already master and for which I’m more than confident I can better harness the code generator. The basic idea is to get a version of the same setup/loop idea, using the direct COM based protocol that is described inside the User Manual provided by the manufacturer which appears to be mostly SCPI/IEEE488.2 compatible. And sure enough, this generated a set of code files that make much more sense to me, even if the output is less “sexy”: 2026-06-26 17:00:41,734 INFO - Opening COM6 @ 115200 baud 2026-06-26 17:00:41,767 INFO - Logging DC voltage at max speed. Ctrl+C to stop. 2026-06-26 17:01:14,492 INFO - Stop requested (Ctrl+C)... 2026-06-26 17:01:14,514 INFO - Done. samples=1306 rate=39.9 Hz errors=0 And with this I am now able to “see” the noise that gets picked when the leads are left floating: I’m not sure where it’s coming from exactly, but with so many electronic gadgets around, it’s not surprising to see this. Next steps would be to make the type of measurement configurable from the command line, allow to read both displays at once, something well within my reach, with or without any help from a stochastic parrot. In the end, I’m glad I chose the DMM as the challenge prize, its logging capabilities will allow me to measure and trace long running variations in the future. Thanks to E14 for this opportunity and to all the community members that keep answering my sometimes dumb questions.loggingdmmhttps://community.element14.com/technologies/test-and-measurement/b/blog/posts/analog-discovery-3---oscilloscope-channels-crosstalkMon, 15 Jun 2026 16:00:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:c0041ad5-3587-46a9-a8b7-a3e3e2cda879kk99The channel isolation describes how much signal on one input channel unintentionally appears on another channel. In case when we are measuring some signal, e.g. on channel 1 and has channel 2 not connected to any signal, in an ideal scenario, there should not be any signal on channel 2. In reality, the tiny portion of signal from channel 1 may leak into channel 2. This parameter is important, especially when we perform measurements of a very small signal on one channel while a large signal on the other. Often this parameter is present in the specification of the measuring instrument. I have checked how it looks in the case of Analog Discovery 3. Measurement To evaluate this parameter, the channel 1 of the signal generator was configured to produce a 1 Vpp signal at 5 MHz. The generator output was connected to channel 1 of the oscilloscope, and channel 2 was terminated with a 50 Ω load. The signals on both oscilloscope channels were measured, and their FFTs were calculated. In the first scenario, Dupont wires were used. The setup and measurement results are presented below. The amplitude of the 5 MHz component was -3.64 dBV on channel 1 and -37.92 dBV on channel 2. The measured crosstalk between the oscilloscope channels was therefore approximately -34.3 dBV. The similar measurement was done for case of usage of the BNC adapter. The setup and measurement results are presented below. The amplitude of the 5 MHz component was -3.52 dBV on channel 1 and -42.47 dBV on channel 2. Therefore, the measured crosstalk was approximately -39.0 dBV. Compared to the measurement performed using Dupont wires, the BNC adapter reduced the observed crosstalk by approximately 4.7 dBV. Summary The measured crosstalk values are consistent with the general design goals of the Analog Discovery 3. Similar to the previously evaluated noise performance, the device was not designed as an ultra-low-noise or high-isolation measurement instrument. For example, the oscilloscope channels do not appear to be individually shielded internally, which can contribute to increased channel-to-channel coupling. Probably the ADP2230 series and particularly the ADP3450 or ADP3250, are expected to achieve better results in this area. The recently introduced ADP2440 and ADP2450 series may also provide improved channel isolation. However, Digilent does not currently specify channel-to-channel crosstalk in the published specifications for these instruments.digilentAnalog Discovery 3https://community.element14.com/technologies/test-and-measurement/b/blog/posts/siglent-spd1305xTue, 09 Jun 2026 17:49:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:6816ac81-a48d-40d9-8e62-a299b64cc4c6kk99Today arrived my power supply, that bought few days ago. It was a good occasion to buy almost not used device in half of current price. The device is in the condition as described by the previous owner. It still has a product seal. After disassembling the cover, there was a bit of dust, but everything looked fine. I just cleaned it with compressed air. I have performed quick tests, and it looks like everything works properly. The regulated fan is very silent, especially if I compare it to the SDS824X HD scope, which is a bit noisy. Below a measurement from OFF-ON and OFF-ON transitions with a connected load 51.1 Ohm resistor. The power supply was set to 8V and 40mA.power supplieshttps://community.element14.com/technologies/test-and-measurement/b/blog/posts/analog-discovery-3---oscilloscope-noise-floorSun, 31 May 2026 18:38:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:e870f0e7-0e8a-45dc-9274-e878c7d3ff8ekk99Background Today I have checked the input noise floor of the oscilloscope channel in Analog Discovery 3. By default, both oscilloscope channel inputs of the Analog Discovery 3 are not shielded. It is mentioned in this thread: https://forum.digilent.com/topic/30475-analog-discovery-3-vs-pro-channel-crosstalk/ It makes sense as dupont wires or non-shielded adapters can catch electromagnetic or radio frequency interferences. Apart from that, the way the AD3 is powered could also influence noise floor. I focused mainly on the way of powering AD3. Test setup Analog Discovery 3 with connected BNC adapter without connected any wire to the adapter. Measured voltage peak to peak, RMS and FFT. Scenario 1 The notebook is powered only by a internal battery with connected AD3. Scenario 2 The notebook is powered only by a wall charger with connected AD3. Scenario 3 The notebook is powered only by a internal battery with connected AD3, which is powered by an external charger via AUX input. Scenario 4 The notebook is powered only by a powerbank with connected AD3. Results Scenario Vp2p_mean [mV] Vrms_mean [mV] 1 1.44 0.20 2 10.70 2.26 3 16.62 2.42 4 3.34 0.59 The best results are when AD3 is powered only by only from a notebook or an external powerbank.oscilloscopeAnalog Discovery 3