App note: 18pF crystals may not oscillate with energy saving MCUs

App note from Abracon about problems due on large crystal capacitive loading on smaller sized MCUs. Link here (PDF) The 18pF plated Quartz Crystals may no longer be the ideal choice for a typical clocking circuit using an off-the- shelf MCU. As silicon geometries have shrunk over the last decade, the Pierce oscillator loop embedded […]

App note: PCB trace vs. chip antenna design considerations

Abracon lists the requirement which antenna type best fit to your application. Link here (PDF) The modern urban environment poses a challenge to high-speed designs involving Cellular, GNSS, WiFi/Bluetooth/BLE/ZigBee and LPWA protocols: the reflection, refraction, scattering, diffraction, polarization and absorption of signals necessitates highly efficient RF chains. Of all components in the chain, the antenna […]

Repairing a vintage 40-kilovolt xenon lamp igniter

Ken Shirriff writes: What do xenon lamps and the invention of radio have in common? The box below is a 1960s German high voltage unit that CuriousMarc obtained as part of an auction. After some research, we determined that it is an Osram1 igniter2, which generates a 40-kilovolt pulse3 to ignite a xenon arc lamp. […]

App note: Cable compensation of a primary-side-regulation power supply

Another tech note from Richtek on power supply regulation with cable compensation. Link here Cable compensation has been used to compensate the voltage drop due to cable impedance for providing a regulated charging voltage in battery charger applications. This application note uses a novel cable compensation method, which called cable minus compensation, as an example […]

App note: Analysis of buck converter efficiency

Tech note from Richtek on buck converter profiling. Link here The synchronous buck circuit is wildly used to provide non-isolated power for low voltage and high current supply to system chip. To realize the power loss of synchronous buck converter and to improve efficiency is important for power designer. The application note introduces the analysis […]

MCP4141 based digital potentiometer

Dilshan Jayakody has been working on an open-source hardware project MCP4141 based digital potentiometer, that is available on GitHub: The main objective of this project is to create an experimental prototype of a digital potentiometer using Microchip’s MCP4141 IC. MCP4141 is available with end-to-end resistances of 5KΩ, 10KΩ, 50kΩ, and 100KΩ. This potentiometer-module can drive […]

Inside a Titan missile guidance computer

Ken Shirriff has written an excellent in-depth look at a Titan missile guidance computer: I’ve been studying the guidance computer from a Titan II nuclear missile. This compact computer was used in the 1970s to guide a Titan II nuclear missile towards its target or send a Titan IIIC rocket into the proper orbit. The […]

DIY long lasting voltage regulator circuit for Raspberry Pi

Jithin @ rootsaid.com writes: Raspberry Pi is simple, handy and cheap yet powerful single board computers of all time. It has USB ports to connect hardware such as pen drive, keyboard, mouse, HDMI port for display out, 3.5 mm port for audio and several GPIO pins to work with embedded projects, all of which can […]

Building my own 50Ah LiFePO4 lithium battery pack

Kenneth Finnegan posted his DIY 50Ah LiFePO4 lithium battery pack build: Several years ago, I had purchased a 20Ah 12V Lithium Iron battery pack from Bioenno for my various 12VDC projects. To help protect it, I ultimately built it up into a 50cal ammo can with a dual panel-mount PowerPole connector on the outside, which […]

Low cost open source ventilator

Johnny Chung Lee writes, “In the event that COVID-19 hospitalizations exhaust the availability of FDA approved ventilators. I started documenting a a process of converting a low-cost CPAP (Continuous Positive Airway Pressure) blower into a rudimentary Ventilator that could help with breathing during an acute respiratory attack. If interested, follow along the Github Project“ More […]

Looking inside a vintage Soviet TTL logic integrated circuit

Ken Shirriff examines a 1980s chip used in a Soyuz space clock: The clock is built from TTL integrated circuits, a type of digital logic that was popular in the 1970s through the 1990s because it was reliable, inexpensive, and easy to use. (If you’ve done hobbyist digital electronics, you probably know the 7400-series of […]