> >Can you make a little amplifier using a single 2n2222 transistor? Certainly. Look up class-A amplifiers. Alternatively, you can use the transistor as an open collector driver, which is a class-C amplifier. -- Dave's Engineering Page: http://www.dvanhorn.org Got a need to read Bar codes? http://www.barcodechip.com Bi-directional read of UPC-A, UPC-E, EAN-8, EAN-13, JAN, and Bookland, with two or five digit supplemental codes, in an 8 pin chip, with NO external parts. -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu