Transistor Matching VBE NPN PNP Board

[synchroma]

Hello there.

I've been using this board to match transistors to 200uVbe. It's a combination of the NPN and PNP Vbe test circuits from Ray Wilson.

Single-sided, but you'll see that there are wire jumpers involved, but it's easy to make and use if you have etching facilities.

IMPORTANT: Due to some mistakes in the transistor library I'm using in Designspark, the schematic puts 2N3904 and 2N3906 transistors THE WRONG WAY AROUND on the PCB, so they have to be rotated 180 degrees. HOWEVER - if you use BC547 and BC559 transistors, the semi-circular transistor symbols on the legend are the right way around!!!

Obviously I thought I goofed when I was building it, because I used SIL sockets for the DUTs, but they require force to get the transistor into them which you really can't do with plastic tweezers. So, I used a stackable arduino header plugged into the SIL and it worked perfectly. You could get 4-pin stackable headers, cut off a pin and then solder them in BUT... one advantage of plugging the stackable header into the SIL - you can straighten the transistor leads out to fit the SIL before you put it into the anti-static foam in the stream of air (the fan is off to the left) making the transfer to the test rig much less hassle when you come to test. I used ice cube trays to separate out transistors to within 200uVbe.

Here are the files, 600dpi board layout, legend and schematic. Don't forget to read Ray's article before you use this setup. Jumpers are indicated as in you connect the -10V terminals together, and the +10V terminals together.

From: http://www.musicfromouterspace.com/analogsynth_new/TRANSISTORMATCHER/TRANSISTORMATCHER.html

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RJW_NPN_PNP_Vbe_Test - Bottom Copper.png
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RJW_NPN_PNP_Vbe_Test - Legend.png
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RJW_NPN_PNP_Vbe_Test_Schematic.png
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Trans_Test.png
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[IImyment]

Thanks,
I'll etch it on my next session exactly what I need