Kerry Wong discussed how to accurately determine a fuse’s current capacity non-destructively: A fuse is a sacrificial device for the protection the rest of the circuit in an over-current situation. There are situations we need to know with some reasonable confidence what the actual maximum current is for a given fuse without destroying it. This […]
Category Archives: testing
Pogo pins + laser cutter = test fixture
Eric Gunnerson made this DIY pogo-pin test jig: I decided to build a pogo-pin test jig, and since the approach I came up with was different than the other approaches I’ve seen I thought it would be worth sharing. I’m going to be targeting my laser cutter for fabrication, though I could have chosen to […]
Experiments with a Hydrogen Thyratron
Kerry Wong did some experiments with a TGI1-50/5 hydrogen thyratron: The one I picked up is a TGI1-50/5 hydrogen thyratron. As the name suggests, it uses ionized hydrogen gas as the switching medium. Hydrogen thyratron typically utilizes titanium hydride in it’s reservoir and the hydrogen gas is released when the reservoir is heated and recombined […]
SI5351 signal generator test gadget
DuWayne published a new build: I have been spending way too much time playing with the new 3D printer, so have to get back to some electronics. Since the next CWTD.ORG episode is coming up, I decided to build another ‘Test Gadget’. This time it is a Signal Generator based on the SI5351 clock generator. […]
DC voltmeter test gadget
DuWayne posted an update on his test gadget project we covered previously: The picture shows the completed DCVM test gadget in 4 channel mode measuring the 3 voltages present on the headers used to connect the individual test gadgets. I was running this off of the PC without the 12 volts connected for external power, […]
ESP32 and the CWTD ‘Test gadget’
DuWayne published a new build: I have been following a series of podcasts from ‘Chatting with the Designers’ CWTD.ORG that cover building simple Arduino based test equipment. I decided that this would make a nice way to get into development with the ESP32. The CWTD ‘Test Gadget’ is basically an Arduino Nano with a 2 […]
Testing the TPS61092 boost converter
Testing the TPS61092 boost converter from LuckyResistor: For my current project I searched for a good boost power converter which is able to deliver continuous 400mA power for various sensors. There are an endless number of good boost converters around, but not many can be hand soldered to a board. I would really like to […]
Simulating 3-phase AC for energy monitor testing
Tisham Dhar blogged about his 3-phase synthesizer: Finding 3-phase is difficult, convincing the owner of the said supply to test some home made hardware is even more so. After building a 3-phase energy monitor my testing options for it appeared very limited. So I set about making my own low-cost 3-phase energy monitor calibration system. See […]
Build your own testing/programming jig
Sjaak has published a new build: Inspired by an old article from sparkfun and some tests I conducted myself I came up with a PCB that holds the pogopinholders and an lasercut acrylic fixture for the PCB on top. Using the dirt(y)cheap services from dirtypcbs.com the cost for this jig, including pogopins and their holders is […]
Pogo pin test board for ADB-USB Wombat
A pogo pin tester for the ADB-USB Wombat board from Big Mess o’ Wires: Here’s a test rig for the ADB-USB Wombat board: my first-ever project whose sole purpose is to facilitate testing of another project. It uses spring-loaded pogo pins to create a bed of nails that fit into test points on the Wombat board. […]
Playing with a surplus E-ink module
Sjaak @ smdprutser.nl writes: When I was in China last year I sourced a couple of small E-ink displays (GDEH0124S01) through Taobao. They were simple ones with 8 14 segment characters. After some searching on the Chinese website from the manufacturer I found the datasheet. It was by all means not complete and a lot […]
DIY programming adapters
Sjaak writes: Today came in a new batch of PCBs from DirtyPCB.com, of which one is a new revision of the BlackMagicProbe. This revision is almost the same except it has a polyfuse in its powersupply to the target, a dedicated voltage regulator instead of P-FET, its programming header on the 90 degree on the […]
Simple crystal tester
Dilshan Jayakody writes: This is simple Colpitts oscillator to test commonly available passive crystals which range between 2MHz to 27MHz. This unit must connect to an oscilloscope and/or frequency counter to get the frequency of the crystal. This circuit is design to work around 9V to 12V DC power source. Both 2SC930 transistors can replace […]
LM2596 DC-DC converter module testing
Kerry D. Wong writes: In the video below, I tested this DC-DC converter board under various operating conditions and measured its efficiencies. To conclude, these switching regulator boards are well suited for low to medium current draw digital circuitry but for higher current applications a heat sink is needed and even so I would not […]
Talk SPI to EEPROM part3: Test SPI Protocol with Bus Pirate
Jan Cumps tested out SPI Protocol using a Bus Pirate: It wasn’t my initial intention to use the Bus Pirate. But my first naive attempts to talk from Hercules to EEPROM failed. I could create the SPI instructions with the LaunchPad, but I didn’t get a reply back from the 25LC256. It’s in these cases that […]
Cheap USB LiPo charger notes
Jim writes: Since I use a variety of cells, I wanted to be able to charge at Chip2014under 1A. Most such charge controllers have a single resistor that programs the bulk charge current, so I looked for the datasheet to find what values I’d need for the charge currents I wanted. The chip is marked […]
Visualizing comparator and Op Amp hysteresis
Kerry Wong writes: Hysteresis can be added to a comparator circuit to improve its stability, especially when the input signal is noisy. In this post, we will examine the hysteresis characteristics of some common comparator and Op Amps using an oscilloscope. Perhaps the most intuitive way to visualize the hysteresis in a circuit is to […]
Tektronix RSA306 IF frequency verification
KF5OBS writes: After posting the teardown video of the Tektronix RSA306 USB 3.0 Spectrum Analyzer on my YouTube channel, someone asked me to verify that the IF sampled by the Linear Technology 14-Bit / 125 Msps ADC is really at 140 MHz. Using the Tektronix MDO4104B-6 and a passive RF probe, I gladly did so.
Temperature data logger using PIC12F683 and DS1820
Rajendra over at Electronics Lab wrote an article on his temperature logger based on a Microchip’s 8-pin microcontroller, PIC12F683: A data logger is a device that records measurements over time. The measurements could be any physical variable like temperature, pressure, voltage, humidity, etc. This project describes how to build a mini logger that records surrounding temperature […]
BJT in reverse avalanche mode
Kerry Wong writes: Transistors operating in their avalanche regions are often used to generate fast rise pulses (see avalanche pulse generator using 2N3904). Many transistors can also avalanche when the connections to collector and emitter are reversed. When operating in reverse avalanche region, these transistors are sometimes referred to as negistors. Because the asymmetry and […]