Elenco Upgrade Kit SC500 to SC750 - Manual (Page 60)

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Project #633
OBJECTIVE: To control the alarm IC with an oscillator circuit.
Oscillator Alarm
Set the adjustable resistor (RV) to the far left and turn the slide switch (S1) on.
The speaker (SP) sounds only once. Slowly move the adjustable resistor to the
right, the speaker momentarily sounds. As you move the adjustable resistor to
the right, the alarm is on continuously. The adjustable resistor controls the
frequency of the oscillator circuit (C3, C5, Q1, Q2) by adjusting the voltage at
Q2’s base. The relay (S3) switches the alarm IC (U2) on and off.
Project #635
OBJECTIVE: To control the space war IC with an oscillator circuit.
Tapping U3
Set the adjustable resistor (RV) to the middle position and turn the
slide switch (S1) on. This is another example using the oscillator that
switches the power on and off creating sound. Alter the sound by
adjusting the adjustable resistor.
OBJECTIVE: To control the alarm IC with an oscillator circuit.
Oscillator Alarm (II)
Project #634
Using a single snap, connect the red LED (D1, “+” side on point A)
across points A & B. Turn the slide switch (S1) on and the circuit has
a different sound now.
OBJECTIVE: To control the space war IC with an oscillator circuit.
Tapping U3 (II)
Project #636
Connect the motor (M1) across points A & B. Set the adjustable
resistor (RV) to the middle position and turn the slide switch (S1) on.
Now you hear random noise and static from the speaker (SP). The
motor causes the random static and noise from the speaker.