Author Archives: DP

ESR measurement using multimeter and function generator

Kerry Wong has written an article discussing the measurement of capacitor ESR using a multimeter and a function generator: Capacitor ESR (Equivalent Series Resistance) measurement is very useful in diagnosing issues with power supplies. In linear power supplies, a high ESR filter capacitor may cause excessive ripple current on the voltage rails and can cause […]

#FreePCB via Twitter to 2 random RTs

Every Tuesday we give away two coupons for the free PCB drawer via Twitter. This post was announced on Twitter, and in 24 hours we’ll send coupon codes to two random retweeters. Don’t forget there’s free PCBs three times a every week: Hate Twitter and Facebook? Free PCB Sunday is the classic PCB giveaway. Catch […]

Hong Kong/China dual number data SIMs with quality internet

Cross boarder SIM cards from China Mobile and China Unicom promise a single SIM that works in Hong Kong and China. Mobile data networks exit at the SIM card home location, so that means Hong Kong internet while in China. These SIMs are sold by two of China’s biggest state owned phone companies, they’re totally […]

Making PCB vias with conductive ink

Here’s an alternative method for making PCB vias using conductive ink from Diyouware: We developed an alternative method for making PCB vias through-hole using our robot. As you probably know the traditional DIY method consists in threading a wire through the holes and then soldering it and then cutting it off. For example, if we have 100 vias in […]

Seeed Studio’s Annual Big Sale Holiday: Seeeday!

Huge saving @ Seeeday! Collect Seeeday coupons for $0 shopping: Seeeday comes from word “Seeed Day”. It is Seeedstudio’s special sale holiday, and it is a one day only event that takes place on the second Wednesday of December every year. It will be on December 9th this year. We offer screaming deals on various items […]

App note: Protecting the Universal Serial Bus from over voltage and overcurrent threats

An old application note from Littelfuse about USB protection. Link here (PDF) This application note addresses the various requirements for protecting the Universal Serial Bus (USB) from overcurrent and overvoltage environmental threats. The solutions presented cover both USB 1.1 and the higher speed USB 2.0 circuitry. Specific emphasis is placed on USB 2.0 with information […]

App note: Automotive circuit protection using Littelfuse automotive TVS diodes

An interesting app note from Littelfuse about automotive circuit protection but also discusses about where transients came from in an automotive setup. Link here (PDF) The designers of automotive electronics face many technical challenges during the system design process, including designing methods of protection against a variety of electrical hazards. The three major sources of […]

App note: AVR32 UC3 USB host mass storage bootloader

USB host mass storage bootloader (PDF!) app note from Atmel: Features • In-System Programming (ISP) and Field Upgrade – Configurable Start Condition with an Upgrade Firmware File ‘avr32fwupgrade.uc3’ Located on a USB Device Implementing the USB Mass Storage Class • USB Protocol – Based on the USB Host Mass Storage Class (MSC) • USB MSC […]

Free PCB coupon via Facebook to 2 random commenters

Every Friday we give away some extra PCBs via Facebook. This post was announced on Facebook, and on Monday we’ll send coupon codes to two random commenters. The coupon code usually go to Facebook ‘Other’ Messages Folder . More PCBs via Twitter on Tuesday and the blog every Sunday. Don’t forget there’s free PCBs three […]

Rigol DSA875-TG 9kHz – 7.5GHz Spectrum Analyzer & tracking generator review, teardown & experiments

Rigol DSA875-TG 9kHz – 7.5GHz Spectrum Analyzer & tracking generator review, teardown & experiments from TheSignalPath: In this episode Shahriar takes a close look at the top-of-the-line Rigol DSA875-TG 7.5GHz Spectrum Analyzer. This unit which, offers a built in tracking generator for the full frequency range, has a portable form-factor. I offers the following performance: 9 […]

Global Geek Tour mini site with maps, comments, resources

Geek tourism is a thing. Travel somewhere new, eat the food, drink the beer, and check out the local hacker scene. In Shenzhen we see 5 or 6 visitors a week. Whether a side trip to Akihabara, or a full on expedition through Huaqiangbei, don’t leave home without bookmarking the Geek Tour mini site. Maps […]

The Sproutie “SPT” Beacon – A legal, unlicensed HiFER beacon

Dave Richards (a.k.a. AA7EE) has written an article detailing his “SPT” Sproutie HiFer beacon project: My first “proof of concept” at putting together a beacon for this band was to connect an N0XAS PicoKeyer in beacon mode to my Pixie 2 transmitter. With the PiicoKeyer, if you insert the prosign BN at the end of stored […]

#FreePCB via Twitter to 2 random RTs

Every Tuesday we give away two coupons for the free PCB drawer via Twitter. This post was announced on Twitter, and in 24 hours we’ll send coupon codes to two random retweeters. Don’t forget there’s free PCBs three times a every week: Hate Twitter and Facebook? Free PCB Sunday is the classic PCB giveaway. Catch […]

Repairing a Marconi Instruments 2955A Radio Communications Test Set, part 1

Mikko has written an article about Marconi 2955A repair: First off, I decided to see what was the deal with the CRT. I have never worked on CRTs before, I have understanding of how the picture is formed by steering the electron beam using the deflection coils but that’s about it. I know a charged CRT […]