Soldering Tips — Karen Douglass / 2004

PCBoard Soldering can be a kind of art form, when done properly. The result should be a perfect physical and electrical connection, between the part lead and the solder pad on the board. I recommend that you find some solder with low lead content, and rosin core. This can help reduce the amount of lead being dumped into our landfills. You should also have a good soldering iron. Be sure the tip size is appropriate for the job. I suggest a 1/8” 3mm screwdriver tip. Hold the iron tip on one side of the joint (where the part lead and… More...

Matching Devices — Nelson Pass / 1993

After you acquire the devices, you will need to test them. You might consider running lots of tests on these transistors, but only one is essential: measuring gate-source voltage versus current. The greatest variations occur here, and it is necessary to do some matching to get proper performance. This test will also tell you whether or not the device is broken. The test is simple and requires a power supply, a resistor, and a DC voltmeter. Figure 12 shows the test hookup for N- and P-channel types. The supply source resistance (R1) is nominal, and is found from I =… More...