Triad-finishedAs promised, the second part of the build showing the finished project. First of all the Cadsoft Eagle schematic and boards. The schematic is not my own but from Mats Engstrom. He posted the schematics on github, I only modified the board to be single sided. Well actually there are two single sided boards on top of each other so that make it semi double sided.

The small board was attached by 3 wires that were soldered on both PCB’s. I had two additional via’s planned on the PCB’s but instead of soldering wires I opted to use small screws of 1.2 mm width 4mm long. Mainly because I have a kit of various sizes lying around waiting for a project and it also looks nice.

The build was initially described in part 1 before I really had time to test the board. So here is a picture of the board being finished, but lacking a battery. I hooked it up to a adjustable power supply and gave it three volts and behold the green led starts blinking. After half a minute or so a red led blinks twice and the whole thing goes back to sleep.



The CR2032 batteries, I sourced from Ebay arrived and immediately one found a home in the Triad.



Here is a shot from the PCB copper side. In case you wondered, it’s milled, not etched.

The four big screws are normal ones, 3mm wide and the “legs” are spacers used for computer mainboards. Chances are good that you have those lying around somewhere, else it’s easy to salvage them from a trashed desktop.



Here is a closeup of the daughterboard on the main PCB. Using a marker the outline of a transistor was hand drawn on there. The label seen in the finished picture of the Triad is a normal print on a piece of paper that was then glued to the PCB.



And for science here is nice picture of the screws selection, sourced from Ebay, at hand to find the perfect length to attach two PCB’s together.


One Response to “Traid, the transistor tester – part 2”
  1. […] showed that I soldered them in the wrong way. Giving it a another hard thought I remembered that my Triad transistor tester also works for mosfets. A quick measurement confirmed that I soldered the mosfets in the wrong way. […]