Transcript ppt

Objective:
1.
You will build a simple circuit - two
transistor audio oscillator that will
generate an audio tone in a speaker.
You will need the following parts from your kit:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
Breadboard
10 ohm resistor
47 ohm resistor
120,000 ohm resistor
0.1 uF (104) capacitor
NPN transistor
PNP transistor
9 volt battery lead
4 wires
9 volt battery
Speaker
Use this schematic to construct the experiment.
47 Ohm
120K Ohm
+
9 volts
10 Ohm
Your circuit should like this one.
1.
2.
3.
4.
5.
Connect the 9 volt battery.
Listen to the speaker.
You should hear a tone about 500 Hz.
Do not change the 10 Ohm resistor as this is only in place to
protect the speaker.
Change the 120K Ohm and/or the 47 Ohm resistor, Try a few
different values, how great of a variation in sound can you
produce?
Troubleshooting:
1. Check the battery. Does it have voltage?
2. Are there any breaks in the circuit?
3. Are the transistors in the right way?
By completing this experiment, you should have
heard a tone from the speaker. By changing the
resistors or capacitors, should have changed the
frequency from the speaker
In complete sentences, write what you learned about
an oscillator.