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Test & Tools

28 Posts authored by: shabaz Top Member
A friend gave me a couple of Pomona Insulation Piercing Clips which I thought were pretty neat. Apparently they are quite popular with the automotive repair/test crowd. The clips were something I had not seen before, so thought maybe it would be good to share some pics/video if anyone else has not seen these before either.   In brief, they can connect to banana plugs (there is also a version of clip compatible with multimeter test leads) and then the other end can be hooked over an insul ...
Introduction This blog post discusses a project to build a simple logic analyzer (hobby-grade; it samples at up to 24 Msps, good enough for basic debugging when other tools are not available), but it has a few extra features too. This project could be handy for troubleshooting I2C or SPI when working on projects. It can in theory also be used for generating protocol output too, and for operation as a programmer for microcontrollers and FPGAs.   Nearly all digital electronics nowadays has a ...
Introduction My car battery died recently, and I thought I’d try out an Energizer car jump-starter. This was a new product to me – I had not realized that such compact lithium ion jump starters were available! It reduces the need to find someone else’s car to do a jump-start.   In brief, it is a unit that looks like a USB power bank (it can be used as such) but with a rubber covered flap that has a connector to allow it to connect via a supplied adapter cable to a car bat ...
Introduction For years I’ve been “helping hand”-less. Since I was a kid, the design of the classic helping hands has not really changed - it has stood the test of time, but just for lightweight tasks. For anything large/heavy, it all goes wrong.   Here’s one attempt at solving the problem.. it relies on cheap camera ball-heads and clamps, and a steel base. It can all be built in an hour or two, depending on how fancy a base is desired. Otherwise, it is all plug-and- ...
Introduction Diodes (or p-n junctions) make extremely low-cost temperature sensors! They are convenient, especially since they can be included on the silicon as part of larger designs into integrated circuits (ICs) - it costs almost nothing to include one : ) There are many dedicated ICs of course too, that use a p-n junction as a temperature sensor, and wrap an analog-to-digital converter (ADC) and a simple interface such as I2C around it. Again they are low-cost, and it is not unusual in larg ...
Introduction This short blog post discusses an attempt to make test leads for hopefully better measurements!   Measuring small resistances is really difficult with the usual 2-wire measurement with multimeters. The multimeter will measure the resistance of the leads as well as the resistance-under-test. Although this could in theory be nulled out, the result can still be poor because the connection still depends on the variable resistance between the probes and the device, i.e. contact ...
Introduction One really useful use-case for a VNA is to characterise antennas. When radio transmitters operate, the signal travels with virtually no loss over a cable (often a coax cable) and then is radiated by an antenna. But some of the energy may be reflected back towards the transmitter, if there is an imperfect match. The VNA operates in a manner where it can simulate a transmitter, and observe how much of the signal is reflected back. This provides an indication of how well the antenna is ...
Introduction This short blog post explores the difference between home-made, low-cost, a mid-cost and a high end 50 ohm load! They have many uses. The larger ones are often used to test transmitters, such as for Ham radio or Citizens' Band (CB) radio.   I used the Rohde & Schwarz FPC1500 Spectrum Analyzer in its Vector Network Analyzer (VNA) mode to examine them. There is more detail about the FPC1500 and how vector network analysis is used in the FPC1500 review here.   What ...
Introduction Over the years I’ve tried many sorts of wire strippers, ranging from knives!, cheap adjustable wire strippers, combined crimp/strip tools and so on. I was not happy with most of them. They were either just good for a very limited range of wires, or the results were unreliable and required a lot of effort to provide a good strip without damaging wires, or the tool itself didn’t last as long as desired.   Life is too short, and so a while back I figured it was about ...
Note: This project, by its nature, needs to connect to the mains supply. It shouldn’t be left unattended and should only be constructed and used by engineers. The information is for educational purposes only, and there is no guarantee that it will be safe, even if it is constructed exactly as specified here. It is believed to be safe when connected correctly, and when used in a lab, but as mentioned there is no guarantee and no liability. Furthermore this project is not intended for home ...
Introduction I needed some custom test leads recently and after experimenting with a few types of banana plugs and cables I found a nice combination and set about assembling them. This short blog post contains a possible recipe, i.e. what worked for me. It was also an opportunity for me to use a ferrule crimp tool. The end result was good – it appears to be a reliable set of test leads. (For innovative ideas on test probes, see here: Shop Tips -  Intrusive Meter Probe  ). In t ...
Introduction The tremendous data logging capabilities of the  U1282A were examined briefly in an earlier blog post, where they proved useful for rapid component binning using the Remote Switch Probe, and for observing trends for seeing laser power by heating a thermistor and using the Data Logger software from Keysight.   The high speed logging is so good it was worth at least another blog post. I was curious how easily it could integrate into an existing test environment. This blog p ...
Introduction The U1282A multimeter supports a high speed logging capability which I was keen to test.   By high speed it means approximately 10Hz indefinitely (my test was for 8 hours using the supplied software, I have not tested this software for a longer period yet). The 10Hz rate looks to be a sweet spot, fast enough to be useful for many scenarios, with the extreme accuracy of a multimeter. It makes an incredible data logger. The only limitation would be that one multimeter is never e ...
Introduction In recent days there have been discussions about the Raspberry Pi 3’s temperature. There is an on-chip temperature sensor but according to reports it is inaccurate. How can we really know the temperature of the Pi’s processor? In general, how can temperatures be measured accurately in a lab?   Thus partly in the quest for finding cooling strategies for the Pi 3 and partly because to me it is an interesting subject, I wanted to be able to measure temperature accur ...
  Introduction Having needed an audio cable recently for the lab, I was saddened to see the poor quality of some off-the-shelf pre-assembled cables. I didn’t realize poor audio cables were still a phenomenon in the 21st century. It got me wondering, how can we test and compare cables and complete cable assemblies?   It is an important question because many are forced to spend a small fortune on cables each time any hi-fi or audio/visual product is purchased from stores – ...

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