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Test & Tools

32 Posts authored by: shabaz Top Member
Introduction What is a Measurement Amplifier? Amplifier Circuit Building It Amplifier Noise Frequency Response Building Revision 2.0 Summary   Introduction This blog post discusses an experimental, simple low-noise amplifier project. The amplifier can be used to enlarge tiny signals from sensors, for example for science experiments. Another use-case would be to observe noise on a DC level (for instance power supply noise), or for capturing data for post-proce ...
Introduction This short blog post documents a simple project to measure current in devices that may have low power operation for periods, but possibly have periods of high current draw. I recently needed to monitor the current of a few wireless devices, and I wanted a way to measure up to an amp or so, but to also be able to resolve tens of microamps in the same range. This is a simple project that can be constructed in half an hour, so there’s not a lot of text to read!     W ...
I had to solder an IC today, nothing new there, but usually I'll use a 1mm conventional soldering tip (slice off conical shape) to solder each individual pin one-by-one, deal with any bridges with desoldering braid, and call it a day.   There are dozens of different ways to solder though. I have a reflow oven, but it is overkill for a single IC. I have a pre-heater and a hot air tool but the ones I have are under-powered.    Although I have seen an expert present drag solderin ...
Introduction What Crimp Pins and Sockets? Crimp Tools Crimp Tools Tested Engineer PA-09 Multicomp HT-225D AMP 90202-2 Crimp Socket Result Photos Crimp Pin Result Photos Heat Shrink Summary   Introduction Making your own jumper cables is quite high on the list of unproductive things to do : ) since they are available ready-made in pin, socket and pin and socket versions. Sometimes I'll just use solid core wire if it is going into board sockets. How ...
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 ...

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