Elenco Upgrade Kit SC300 to SC750 - Manual (Page 22)

-21-
Project #347
OBJECTIVE: Making telegraph sounds.
Press the press switch (S2) down. The circuit oscillates and the AC
voltage generated from the transformer (T1) drives the speaker (SP).
To make a telegraph sound, depress the switch for long and short
periods.
Telegraph
OBJECTIVE: Show variations of project
#347.
Use the circuit in project #347. Connect the
whistle chip (WC) across points B & E.
Mosquito
Sound (II)
Project #349
OBJECTIVE: Show variations of project
#347.
Mosquito
Sound (III)
Project #350
OBJECTIVE: To use the photoresistor to
adjust the oscillator sound.
Touch-Control
Mosquito Sound
Project #351
OBJECTIVE: Use the whistle chip to make a mosquito sound.
Use the circuit in project #347. Remove the speaker (SP). Connect
the whistle chip (WC) across points C & D to make a mosquito sound.
Mosquito Sound
Project #348
Use the circuit in project #347. Connect the
whistle chip (WC) across points E & D (place
it beneath capacitor (C2) or use the jumper
wires). Use the circuit in project #347. Replace the
100k
Ω resistor (R5) with the photoresistor
(RP). Wave your hand over the resistor and
the sound changes.
To learn more about how circuits work, visit www.snapcircuits.net or page 62 to find out about our Student Guides.