Fully-detailed instructions for assembly and test of the PIC-EL Kit.
Section 8: TRANSISTORS
The transistors used in this kit are "bipolar" and thus are not overly sensitive to static, as contrasted to FET or MOSFET devices you may have used with other kits. Therefore you shouldn't excessively worry about handling the transistors in the PIC-EL Kit, but you should still practice the good habit of not shuffling along the carpet while holding the parts in your hand. Another good practice is to often touch a grounded connector on your workbench to discharge any static buildup in your body.
You should pre-bend the middle lead of the black plastic TO-92 packaged transistors (2N2222A and 2N4401) for easiest insertion to the pcb. This is Shown in the two photos below. Using small needle nose pliers, grab the middle lead and pull/bend it backward toward the rounded side of the transistor body.
The first transistor to install should be Q6 (2N4401). Make sure you have the 2N4401 device, as marked on the flat side of the transistor body. Most homebrewers have a lighted magnifying glass to check the designators of small parts. Orient the transistor with the flat side of the body positiined as shown on the board's silkscreened diagram, and the previously-bent leads should align just right with the simi-circular arrangement of three holes. Solder the transistor leads to the pads and snip off excess lead length.
The next devices to install should be the five 2N2222A transistors (Q1, Q2, Q3, Q5 and Q7). These plastic bodied devices should also have their middle lead pre-bent before insertion. Carefully align the three leads as above, the insert, solder and clip off the excess lead lengths.
The final transistor to insert is the metal-canned 2N2907 device, Q4. The correct orientation of this device is such that the little tab on the edge of the can is aligned with the tab in the silkscreened diagram on the board. Make sure the metal body remains just a few few millimeters above the board so it doesn't short out against the pads below, then solder and clip excess lead length.
Although not a semiconductor, per se, you should install the crystal (XTAL) at this point. Similar to the way you left the metal canned transistor slightly above the board, before soldering the crystal in place you should make sure the metal canned body does not touch the board.
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Page last updated: Feb 4, 2004