App note from Maxim Integrated creating voltage negative reference from charge-pump inverter plus positive voltage reference combo. Link here (PDF) This application note discusses how to build a negative voltage reference without using external resistors or a negative supply by simply combining a simple charge-pump inverter and a positive output voltage reference.
Author Archives: DP
App note: Simple test method for estimating the stability of linear regulators
Tips from ROHM Semiconductor to estimate the stability of linear regulator using simple step response method. Link here (PDF) Low drop-out (LDO) regulators developed back in the age when large-capacitance multi-layer ceramic capacitors (hereinafter, MLCCs) were uncommon cause a phase delay, leading to oscillation when connected to a low-ESR capacitor like an MLCC. Often, MLCCs […]
App note: Understanding the safety certification of digital isolators
This application note summarizes the international safety standards and certifications that apply to digital isolators. Link here Digital isolators provide signal isolation and the level shifting required for the correct operation of many circuits. Equally important, they insulate the user from electric shock. With basic human safety considerations so pertinent here, these isolators must undergo […]
Op amp on the Moon: Reverse-engineering a hybrid op amp module
Ken Shirriff has written an article on reverse engineering a hybrid op amp module: I recently obtained a mysterious electronic component in a metal can, flatter and slightly larger than a typical integrated circuit.1 After opening it up and reverse engineering the circuit, I determined that this was an op amp built for NASA in […]
Piggybacking USB onto an industrial push button
Glen Akins has written an article detailing his USB-connected big red button project: In this project, I mount the electronics from my single-key USB keyboard project to the back of an industrial mushroom push button switch. The finished big red button now activates my screensaver with a single overly-large button press. The biggest issues in this […]
Resistive load, constant-current power supplies, and a 3D printed desk lamp
Dr. Scott M. Baker published a new build: In this video, I build a 3D Printed Desk lamp. The basic design came from Thingiverse, but I repurposed my LM2576 Constant-Current design to serve as a dimmer. It all started when I found an interesting lamp on thingiverse, which used 75mm air hose segments from another […]
Sound card ECG with AD8232
Scott Harden built a DIY ECG project with AD8232, that is available on Github: Every few years I revisit the idea of building an ECG machine. This time I was very impressed with how easy it is to achieve using the AD8232, a single-lead ECG front-end on a chip. The AD8232 is small (LFCSP package) but breakout […]
Free PCB Sunday: Pick your PCB
We go through a lot of prototype PCBs, and end up with lots of extras that we’ll never use. Every Sunday we give away a few PCBs from one of our past or future projects, or a related prototype. Our PCBs are made through Seeed Studio’s Fusion board service. This week two random commenters will […]
App note: Reset and supervisor ICs – frequently asked questions
All about supervisor ICs FAQs from STMicroelectronics. Link here (PDF)
App note: Receiving S/PDIF audio stream with the STM32F4/F7/H7 series
App note from STMicroelectronics about electrically connecting an external S/PDIF stream to an STM32 with an S/PDIFRX interface peripheral, Link here (PDF) The Sony/Philips Digital Interface Format (S/PDIF) is a point-to-point protocol for serial and uni-directional transmission of digital audio through a single transmission line for consumer and professional applications. The transmission of data can […]
App note: Addressing power supply challenges for after-market electronics and infrastructure
This application note discusses key market trends and customer needs that are presenting new challenges for power supply design for after-market technologies and transport infrastructure automation. This piece will also examine solutions to address these challenges, with a special emphasis on power architecture. Link here After-market automotive products have driven remarkable innovation, from infotainment and […]
Wifi based DIY 5V switcher for led-lights
Albert posted a detailed how-to on building DIY ESP-12F based USB-5V switcher: 5V powered 100LED circuit was consuming around ~1.8Watts(though 5.1Ohm series resistor was really hot) and the brightness of the LED’s were not bad, especially difference between first led and last led brightness didnt bother me it was hardly noticeable when seen from distance. So […]
So how to do CW on a homebrew SSB rig?
Pete Juliano, N6QW, has written an article on how to do CW on a homebrew SSB rig: The Answer is Not a Flippant: Carefully! Author’s note: A friend in VK4 land made an inquiry about CW operation. I find that 99.99% of my operating time is SSB. But others spend a greater time on the […]
Tiny particle sensor node with decorative case
Lucky Resistor published a new build: This article is about a small sensor node with a decorative case. It is based on the Raspberry Pi Zero W board with a custom sensor shield on top. I publish all hardware files for a simple version of the sensor, so you should be able to build this […]
App note: Bootstrap circuit in the buck converter
App note from ROHM Semiconductor about bootstrap capacitor used in switching regulator chip. Link here (PDF) This application note explains the step-up circuit using a bootstrap capacitor. In buck converters, this circuit is used when the highside switch is the N-ch MOSFET.
App note: Linear regulator problem situations – Power supply does not start
App note from ROHM Semiconductor about various start up problem on 3 pins linear regulator. Link here (PDF) Although linear regulators can be used to easily configure power supplies, the linear regulators may cause startup problems depending on the type of loads. This application note introduces cases where the power supplies do not start correctly […]
App note: Design considerations for a harsh industrial environment
This article discusses factors that influence the robustness of a circuit in a harsh environment, like you would find for industrial applications. The topics covered include ways to handle voltage transients and to protect against electrostatic discharge (ESD) and faults. Link here Semiconductor (IC) robustness—what is the operating temperature range? How is high electrical noise handled? […]
Remote debugging with USB based JTAG/SWD debug probes
Erich Styger wrote an article on how to turn a USB debug probe into a IP-based debug solution: For some projects it is not possible to have the device under debug available on my desk: the board might be in another room, on another site or in a place where physical access is not possible […]
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 […]
Raspberry Pi based indoor air quality monitor
Dr. Scott M. Baker made this Pi-based environmental monitor and wrote a post on his blog detailing its assembly: For years I’ve followed the “uRadMonitor”, a device that does air quality monitoring and radiation monitoring. I’ve played with geiger counter projects before and frankly found them to be not very interesting. However, the idea of monitoring […]