Voltlog #103 – InTheMail

Today we are taking a look at my electronics related mail, I’ve got a bunch of random stuff and links for all of them are provided below the video.

Voltlog #82 – DIY Adjustable Analog DC Electronic Load

In this episode I am building an analog adjustable dc load with parts easily obtainable from ebay and banggood. The advantage of such a dc load is that you can understand how it works, modify or repair it if necessary far easier than you would with a digital one. I was able to push mine up to 60W dissipation, but it is recommend to stay under 50W to protect the mosfet.

Here is a list with links to the parts used in this project:

Voltlog #78 – 2x25W Bluetooth 4.1 Stereo Amplifier TDA7492P

In this episode we are going to build a bluetooth speaker amplifier based on the TDA7492P class D audio amplifier coupled with a Bluetooth 4 module. We are not actually going to build the amplifier module because we can get that from China, very affordable, it only costs around $12 shipped which is way less that it would cost us to buy the bluetooth module and the TDA7492P individually not to mention the cost of fabricating a PCB of this size.

So we are actually going to use this module and build the final product with a nice enclosure and a suitable external power supply

Here are some links for the parts used to build this project:

Wiring diagram below:

Voltlog #76 – InTheMail

This what happens when I left myself on a shopping spree, you get a month’s worth of InTheMail episodes. So let’s get started on the 4th episode in a row showing the stuff I get from China.

Here is a list with the items shown in this video:

  • Brushless Blower Fan 12V 5015S
  • Brushless Blower Fan 5V 6015S
  • Cooling Fan 5V 2 Pin 50x50x10mm
  • Fan Grill Guard 50mm
  • Aluminium Heatsink 150x60x25mm
  • TO-220 Aluminum Heatsink 34x12x30mm
  • 100W Wire Wound Aluminium Housing Resistor
  • 200x175x70mm Plastic Enclosure For Instrument
  • 170x130x75mm Metal Enclosure For Instrument
  • Rubber Feet Self Adhesive 15mm
  • LM2596 DC-DC Step-Down Converter Module
  • XL6009 Buck-Boost DC-DC Converter
  • 10A BMS 3S Battery Protection Module
  • Zener Diode Assortment – Through Hole
  • Zener Diode Assortment – SMD
  • PT4115 LED Driver IC

Links for all of the items will be in the video description on youtube.

Voltlog #64 – DIY Adjustable Power Supply With Enclosure

Today I’m going to be building a complete DIY analog bench power supply. The actual analog power supply kit (0-30V 0-3A) that I’m going to be using, is this one, it was shown and assembled in voltlog #8. Besides that I’m going to be using this plastic enclosure which I think is quite nice and perfect for such a project, this one can also be found on banggood and there will be links in the description for all the items used in this build.

Upgrading Workbench Lights Using 7020 White LED Strips

Although the operating temperature of this LED might be up to 85 deg C, while looking through various datasheets, I couldn’t find a graph showing a plot of the expected life in hours vs temperature. If I were to guess I would say you need to run these at less than 50 degrees C to get some decent life out of them. There was a mention of a stress test in a datasheet and that meant for that particular led manufacturer running it at 60 degrees C full rated current for 1000 hours with no resulting damage.

If you have any info on these LED’s and what temperature they should be running at to get some decent life out of them, please leave a comment below.

So to finish up on this story I have to say that I learned some things about these LED strips. If I were to design something from  scratch I would run some basic thermal calculations based on the figures from datasheets but in this case, with these chinese led strips, there is no datasheet, I can’t even easily compare to existing datasheet because these can’t be compared: the driving current is different, the LED only has one die in my case and so on.

The next thing I will try is to double my L shaped heatsink with another piece the same model and size this way I will be increasing my heatsink surface and hopefully cool the LED’s better, maybe shave another 5 degrees.

I will be posting an update with some measurements for comparison once I get the upgrade done. Links for the power supply, led dimmers as well as the light meter used in this video will be in the description of the video so do check them out.