Elenco Upgrade Kit SC500 to SC750 - Manual (Page 61)

-60-
Project #637
OBJECTIVE: To build a simple oscillator that beeps.
Adjustable Beeper
Turn the slide switch (S1) on and this simple oscillator circuit outputs
a beep from the speaker (SP). Change the frequency by adjusting the
adjustable resistor (RV).
Project #638
OBJECTIVE: To create the sound of a cat’s meow.
Electronic Meow
Turn off the slide switch (S1) and then press and release the press
switch (S2). You hear a “cat’s meow” from the speaker (SP). Now turn
the slide switch (S1) on and the sound is lower and lasts longer. Adjust
the adjustable resistor (RV) while the sound is fading away.
OBJECTIVE: To add the photoresistor to project #638.
Electronic Meow (II)
Project #639
Replace the 10K Ω resistor (R4) with the photoresistor (RP). Wave
your hand over photoresistor as you press down on the press switch
(S2).
To learn more about how circuits work, visit www.snapcircuits.net or page 85 to find out about our Student Guides.