BE Lesson 5: Make an audio oscillator What is a speaker? What is an audio oscillator? How do we make...
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Transcript of BE Lesson 5: Make an audio oscillator What is a speaker? What is an audio oscillator? How do we make...
BE Lesson 5: Make an audio oscillator
• What is a speaker?
• What is an audio oscillator?
• How do we make an audio oscillator?
© 2012 C. Rightmyer, Licensed under The MIT OSI License, 20 July 2012
What’s a speaker (BE demo 5-1)
+
volts
10
BE ckt 5-2. A 500 Hz tone oscillator
+
volts
120K
NPN 3904
B
C
E
PNP 3906B
C
E
+
47
10
0.1 F
Adapted from Electronic Kourseware Interactive, Discover Electronics, www.eki.com
BE ckt 5-2. Hookup diagram
+
9.0
volts
Note: Transistors face down on breadboard
47
3904
ceb
3906
ce
10
0.1 F
b
120K
Note: this circuit works equally well with a 0.1 F electrolytic capacitor.
BE demo 5-3. How BE ckt 5-2 works
BE ckt 5-4. A variable tone oscillator
+
volts
1 Meg pot
NPN 3904
B
C
E
PNP 3906B
C
E
+
47
10
0.1 F
BE ckt 5-4. Hookup diagram
+
9.0
volts
Note: Transistors face down on breadboard
47
3904
ceb
3906
ce
10
0.1 F
b
1 Meg pot
BE Lesson 5 background slides
Make a Post-it speaker
Concept published by the Pioneer Works Center for Arts and Innovation, Brooklyn, New York.www.popsci.com/paperspeaker