1. BE Lesson 9 Make an audio amplifier Use an operational amplifier (opamp) to build an audio amplifier © 2012 C. Rightmyer, Licensed under The MIT OSI License, 20 July 2012

2. BE project 9-1. An audio amplifier using the LM-386 opamp

3. Schematic for the completed audio amplifier Adapted from: http://www.ece.ucsb.edu/yuegroup/Teaching

4. Pinout for LM386N-3 (U2) 1 2 3 45 6 7 8 GAIN - INPUT + INPUT GND BYPASS Vs Vout

5. Hookup diagram for BE ckt 9-1 0.1  F 10  F 123 4 5 6 7 8 100  F + 0.033  F + 470  F place speaker face up 10K 10  + + 1  F 9v Stereo input D1 and D2 = 1N4148 D1 D2

6. BE project 9-2. Bonus Velleman audio amplifier kit K4001

7. Background slides for L9

8. Frequency response of an ideal audio amplifier Http://forum.ecoustics.com/bbs/messages/34579/131062.html

9. A typical high-quality amplifier’s frequency response curve Http://forum.ecoustics.com/bbs/messages/34579/131062.html

10. Frequency response with a lower quality amp Http://forum.ecoustics.com/bbs/messages/34579/131062.html