Voltlog #72 – DIY AC-DC Off-Line Converter With TNY276/TNY277

This is the first AC-DC power supply that I’m designing and building. Everything seems to work up to a point where the chip (TNY 276 from Power Integration) gets too hot and enters thermal protection. This is where I’m asking my viewers help to jump in with suggestions on what might be wrong.

This is part 2 where I get the circuit working by switching from the TNY276 to the TNY277 which has a higher power rating and is probably the proper IC to use with this transformer (EE1616 ER2741)

And this is part 3 of the video where I finally find the real fault in the circuit. It turns out I was right, this circuit should have worked with the TNY276 as well and it wasn’t the higher power rating of the TNY277 that fixed the issue.

Voltlog #71 – Electronic Touch Musical Keyboard Kit

A while ago I saw this touch musical keyboard kit on banggood and it seemed interesting enough to order one. It turns out the kit is using a single atmega8 to do all the touch sensing (8 ch) and play the tunes accordingly. Although not very useful for me it sure was fun to assemble and play with.

Voltlog #69 – LM317 Kit Assembly Fail

Sometimes, when I have some spare time I like assembling these cheap kits coming from China. Today I am assembling an LM317 adjustable power supply kit complete with voltmeter. Unfortunately they sent me a wrong resistor value so the kit didn’t work as expected but I was able to fix it in the end.

Voltlog #68 – InTheMail

A new InTheMail video containing a bunch of different stuff i got from China. If you like these videos don’t forget to subscribe to my channel and hit the like button because that always helps.

List of items shown in this video:

  • HAKKO FG-100 (clone) Soldering Iron Thermometer
  • A6 GSM/GPRS Breakout Module
  • Sharp Multimeter Probes 1000V 20A
  • TEC1-12706 Peltier Modules
  • Plastic Bottle With Needle
  • Universal Power Socket With Dual USB Charging Port
  • 14 Types Tactile Switch Push Button Set
  • Ceramic Fast Blow 1A 250V Fuse
  • Outdoor Waterproof Shockproof Airtight Survival Case

Links for all of these will be in the video description on Youtube.

Voltlog #67 – Precision Current Reference Using REF200

A while ago I watched a video from Scullcom Hobby Electronics channel where he build a precision current source, a very simple but accurate one. If you don’t know this channel I encourage you to subscribe to it, it has allot of nice videos on lab equipment either building DIY versions or reviewing existing ones. Each video has nice drawings and the guy clearly knows what he is talking about so a great resource for learning.

I don’t have any current source in my lab, and these are useful for testing multimeters for example. I was looking on ebay for a current source but I wasn’t able to find an affordable one so I’ve decided to build one using the project information from that video and I will link the video in the description below, it’s nice to watch it has lots of interesting explanations so I won’t repeat them in this video, I will mostly focus on showing you how I build and improved my current source.

Voltlog #66 – Cheap NiMH Rechargeable Battery Testing

If you were following my InTheMail videos you probably seen these green rechargeable batteries that I got from ebay quite cheap, I think they were like 50 cents a piece. I got 4 pcs in AA size and 4 pieces in AAA size and little did I know about how crappy these could be.