Elenco Projects PC1-PC73 - Manual (Page 35)

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Project #PC21
Buzzing in the Dark PC
OBJECTIVE: To build a circuit that buzzes.
Build the circuit shown. If continuing from the previous experiment
then close the Winscope program and run it again, to reset the
settings. Set Winscope to the
settings shown below and click on
the On-Line button to activate. A sample waveform is shown here.
The actual waveform will vary depending on how much light is
shining on the photoresistor (snap part RP).
If you cover the
photoresistor then the circuit shuts off.
Settings
The waveform above is weak and
erratic, so replace the 0.02
m
F
capacitor (snap part C1) with the
0.1
m
F capacitor. A sample of the
new waveform is at left, with the
same settings.
It is lower in
frequency but higher in amplitude.