Elenco Electronics 202 - Manual (Page 90)

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OBJECTIVE: To build a high pitch bell.
Build the circuit shown and press the press switch (S2). The circuit
starts to oscillate. This generates the sound of a high pitch bell.
Using the circuit in project #208, connect the 0.1 μF capacitor (C2)
across the 0.02 μF capacitor (C1). Press the press switch (S2). The
circuit now generates the sound of a steamship.
Project #208 High-pitch Bell
Project #210
OBJECTIVE: To use your body as an electronic component.
Wet Finger Detector
Turn the circuit on, nothing happens. Touch points A & B with your
fingers, nothing happens. Wet your fingers with water or saliva and
touch points A & B, you hear a loud tone.
Wetting your fingers makes better electrical contact with the metal,
effectively lowering your body’s resistance.
OBJECTIVE: To generate the sound of a steamship.
Project #209
Steamship