Category: Soldering

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 #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 #47 – ICL8038 Frequency Generator Kit Assembly

Today we’re going to be assembling this frequency generator kit based on the ICL8038 which I got in an earlier InTheMail episode. The ICL8038 waveform generator is a monolithic integrated circuit capable of producing high accuracy sine, square, triangular, sawtooth and pulse waveforms with a minimum of external components.

Voltlog #45 – Multiple Rail Power Supply Kit Assembly

In this video I am assembling a multiple fixed rail power supply kit. This power supply works with a 5-24V input either through a USB mini socket or a dc barrel jack (2.5mm center positive) and at the output you get +12V, -12V, +5V, -5V and +3.3V. My kit was missing 1 small heatsink and one of the electrolytics was a different value than specified on the PCB.

Voltlog #42 – DIY 4 x 18650 Battery Charger

Today we’re going to be making a DIY lithium battery charger and more specifically aimed at charging 18650 cells. I sometimes take apart some of these laptop batteries to recover 18650 cells and I have a bunch so far that I kept. Every-time I salvage these cells I test them before deciding to keep them or not.

As you can imagine it takes time and I need to charge multiple cells at once. So I will be making a charger that can handle 4 x 18650 cells but the project is scalable and you can increase or decrease the number of cells it can handle according to your needs. As usual, links for all the items will be in the video description.

Voltlog #35 – SMD Assembly And Reflow

In this video I am going to show you how I assemble PCBs with surface mount devices. First I apply the solder paste with the help of a stainless steel laser cut stencil, next I manually pick and place all the components and the last step is to run the boards through a reflow profile in my DIY reflow oven.