Wednesday, June 11, 2014

LED VU Meter with LM3916

This was finished months ago and just now I had time to finish the article. LM3916 is a dedicated IC for VU LED meter.  Unlike LM3915 which have 3dB step between voltage levels, the LM3916 have nonlinear steps: -20, -10, -7, -5, -3, -1, 0, +1, +2, +3db, just like old school analog VU meters. I saw in YouTube an interesting commercial LED VU meter, which imitates the needle movement in analog VU meters and I thought I can make a similar one. All I needed I found in the datasheet of LM3916.

Saturday, April 12, 2014

Simple timer with PIC16F628A

This is a quick project for a timer. Recently I finished my UV light exposure box and thought that it will be convenient to have a build in timer to switch off the light after preset time.
So I had a PIC16F628A lying around and after searching the web I found a Brazilian site (I think?) with tons of interesting projects with microcontrolers. This project is based on one of them.

Wednesday, March 5, 2014

50W Power Amplifier with LM3886

This is my second encounter with LM3886. I was pleased of the sound this chip produced the first time, so I decided to make another amplifier with it.

Saturday, October 19, 2013

Troubles with charger

A couple of months ago I bought a Chinese Android tablet Cube U35GT2 , which is quite nice although it has its downsides. One of them is the charger included in the bundle. It is a typical Chinese charger rated 5V/2A and it gets very hot when I use the tablet while charging. Eventually it burned out and I got to repair it - the output filter capacitor was blown up and I replaced it and also replaced the catch diode with a higher rated one.

Sunday, June 23, 2013

Original PICKIT-2

These days I was thinking about a better PIC programmer that can work with Microchip MPLAB IDE software so that I can write my own programs or edit someone else's  programs.
I found that there are numerous versions of the famous Microchip PICkit 2 on the web. Some of them are using the original schematic published by Microchip and some are lite versions - with different parts or simplified schematics. None of them satisfied my requirements. So I got the original schematic, removed the memory chips and the input ICSP connector (which I didn't plan to use anyway) and made a new single sided PCB. I used mostly SMD parts.

Tuesday, March 26, 2013

Adjustable Lab Power Supply - take two :)

So, the previous article about lab power supply gathered quite a interest which is not a big surprise considering that there are over 200 pages of discussions in two topics about the schematic in this forum: http://www.electronics-lab.com/forum/index.php?board=2.0!

I think that the schematic in www.electronics-lab.com is not the original one but a modification of an older schematic published in a Czech electronic magazine. I found it here: http://paja-trb.cz/konstrukce/zdroj.html  There are scanned pages from the magazine with the original article and eagle files for the project.