Instant preamplifiers that you can rapidly build and test! Use our preamp design applets. They run on any PC with a Java-enabled Web browser, such as Explorer. You plug in a few numbers and your computer outputs resistor and capacitor values.

The necessary transistors are general-purpose devices such as 2N2222A or BC-109. The amplifiers aren't fancy, but they work. The programs only specify parts for one stage. You can direct couple more stages by connecting a PNP stage to the first NPN stage. Couple Stage 2 base to Stage 1 collector, and so forth. Only use base bias resistors on the first stage. Succeeding stages alternate between PNP and NPN transistors.

CAUTION: Avoid direct coupling stages where the B-E voltage drop exceeds 6 volts. Otherwise, your transistors will melt. The transistors must have a beta of about 200 at the desired emitter current. Only use silicon, bipolar devices.

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•URL: http://www.hawestv.com/amp_instr/amp_instr1.htm •Webmaster: James T. Hawes
•Revised—September, 2010 •Created by the author primarily in HTML & Notepad •Also used: Word 98 •Disclaimer: The author assumes no responsibility for your success or failure in using methods described on these pages. Further, the author neither makes nor implies any warranty or guarantee as to the accuracy or effectiveness of these methods. Proceed at your own risk.