Tag Archives: electronics

Fix: Samsung Galaxy S3 not charging, charges slowly or charge toggles on and off

s3-charging-smallPretty soon after I bought my brand new Samsung Galaxy S3, it began to be erratic charging behavior. It would often not charge, charge slowly or rapidly switch/toggle between charging and not charging. Searching on the web didn’t yield any good solutions, with most sites arguing about whether the cable, phone, or software was to blame.

The charging cable seemed suspect, since it would work better sometimes if I manually held it at a particular angle. However, even if I used a brand new cable, our car’s USB cable or my wife’s cable (which was still working for her S3), my phone had this problem. After a few months, my wife’s Galaxy S3 started having the same problem. Continue reading Fix: Samsung Galaxy S3 not charging, charges slowly or charge toggles on and off

How to fix: Pantech Jest battery will not charge

My wife’s new Pantech Jest cell phone won’t charge its battery. This has been a recurring problem with new batteries we get for it, too: inevitably it always ends up refusing to charge the battery. If you plug the phone in to charge then the phone will turn on and power up, but it will not give any indication of charging. Then no matter how long it is plugged in, the moment the phone gets unplugged it instantly turns off. The first time this happened our wireless provider replaced the phone, but the new phone exhibited the exact same behavior right out of the box. This meant that the battery was at fault, not the phone, so then our wireless provider replaced the battery which did fix the problem. However, a few weeks later the exact same thing happened. So they gave us another replacement battery (which fixed the problem again). But now this week the same problem has happened a third time. Fortunately there is a solution. Continue reading How to fix: Pantech Jest battery will not charge

DC-DC switching voltage regulator: Buck converter

Power MOSFETWhen I took a power electronics course at MIT (6.334) almost two years ago I instantly fell in love with the simplicity and ubiquity of switching power supplies. They are so simple and interesting that I decided to devote a few posts here describing how they work. Voltage regulators are interesting and useful to learn about because they are used everywhere. Electronic components (for example, those within your home electronics equipment) often require different voltages, so voltage regulators included in the equipment to generate those voltages. The first question to answer in this post is “What is a voltage regulator”: Continue reading DC-DC switching voltage regulator: Buck converter

Epson wireless printer won’t print or show ink levels anymore

I recently installed Windows 7 SP1 (service pack 1), and as a result my Epson NX515 wireless network printer wouldn’t print anymore from my desktop computer. Additionally, when I would go to the printer properties, it wouldn’t show the ink levels anymore. I could ping it, view the memory card storage, and view its built-in webpage, but I couldn’t print to it from my desktop. I tried reinstalling the drivers for it and also tried just about everything else that popped up in the results from my search engine queries.

Eventually I figured out how to get it working on my own. Here’s the scoop on how to fix it. Note that this fix is for if your printer drivers can see the printer, but for some reason when you try to print it give a print error or communication error (e.g., you get an error on the computer, and when you physically look at the printer it appears as though it did not receive any data). Continue reading Epson wireless printer won’t print or show ink levels anymore

Wireless connection disconnects and reconnects randomly (or, wireless droppings stink real bad)

I thought that this little tidbit might be useful to a few people. My netbook’s wireless connection recently started disconnecting and reconnecting randomly at school. This didn’t happen last year, it only started a few weeks ago. Looking up this problem online didn’t give any conclusive answers, but made me believe that some settings got changed either on my netbook (e.g., an automatic driver update), on the routers’ configurations at school (e.g., an updated credential persistence policy or supporting a new standard like 802.11n), or a combination of the two.

My netbook’s disconnect and reconnect problem was fixed by changing two settings on my netbook. Implementing #1 below made the problem a little better, and implementing both made the problem go away completely. Continue reading Wireless connection disconnects and reconnects randomly (or, wireless droppings stink real bad)

Convert 120 V AC to 3.3 V DC without a transformer

I finally made some progress with the AC to DC converter (without using a transformer.) I recently graduated from NAU and got a job, so I actually have a little more time on my hands to work on stuff like this (even with a 3-month old baby.) If you will remember from my previous post on this topic, the challenges facing this project are that it should convert 120 V AC to 3.3 or 5 V DC, handle a relatively high output current (more than 15 mA, and the more the better), have a small profile (so no transformer or huge capacitor,) and draw very little current when no load is attached. Continue reading Convert 120 V AC to 3.3 V DC without a transformer

Final Freqency Synthesizer Design

Unfortunately, I never had the extra time needed to post the progress of the frequency synthesizer school project. However, you can view all the info pertaining to the project at the website I created for the project:
mike-thomson.com/school/Wulfsberg/. (Alternatively you can try to find it posted somewhere at http://www.cefns.nau.edu/Research/D4P/, but they are always changing the address of our project’s page.)

Frequency Synthesizer

The Electrical Engineering Department at Northern Arizona University (NAU, where I am a student) provides a senior level capstone design course for students. The senior students are grouped into teams and work with sponsors to complete an advanced engineering project. Our senior capstone design team is working with our sponsor, Wulfsberg Electronics, and we will be designing and implementing a frequency synthesizer for them. Wulfsberg Electronics is designing a new communication radio product that will utilize newer and smaller parts than those currently being used, and our project will be a part of their new product. Continue reading Frequency Synthesizer