Elenco Projects 102-305 - Manual (Page 38)

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Project #206
OBJECTIVE: To build a high-frequency oscillator.
Tone Generator
Project #207
Tone
Generator (II)
OBJECTIVE: To lower the frequency of a
tone by increasing circuit capacitance.
Place the 0.02 μ F capacitor (C1) on top of the
whistle chip (WC) in the preceding circuit, you
hear a middle-frequency sound. Why? The
whistle chip is used here as a capacitor and
by placing the 0.02
μ F on top (in parallel) we
have increased the capacitance, and doing so
lowers the frequency.
Project #208
Tone
Generator (III)
OBJECTIVE: To lower the frequency of a
tone by increasing circuit capacitance.
Next, replace the 0.02 μ F capacitor (C1) and
the whistle chip (WC) with the larger 0.1 μ F
capacitor (C2). You now hear a low frequency
sound, due to yet more capacitance.
Project #209
Tone
Generator (IV)
OBJECTIVE: To lower the frequency of a
tone by increasing circuit capacitance.
Now replace the 0.1 μ F (C2) with the much
larger 10 μ F capacitor (C3), (orient with the
positive (+) side towards the left); the circuit
just clicks about once a second. There isn’t a
constant tone anymore due to other transistor
properties. You need a different type of circuit
to create very low frequency tones.
Build the circuit and turn it on, you hear a
high-frequency sound.