Data Sheet

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70. Distant Siren with Indicator
Build the circuit and turn ON the switch
(62). A distant police siren will come from
the speaker (93) with the red light indicator
ashing (LED 69). In this circuit the LED
(69) is in series with the speaker (93), the
voltage drop across the LED (69) reduces
the voltage across the speaker (93)
reducing the volume of the sound.
71. Battle Far, Far Away
Turn ON the switch (62). A far away siren
sound effect will come from the speaker.
Touch the touch plate (80) to change the
sounds of a far away gun shot. The red light
indicator will help indicate sounds from the
speaker if the room is noisy and sounds are
hard to hear. These are special effects for
a space battle in a galaxy far away.
72. Many Sirens in the Distance
Turn on the switch (62). A far away siren should come from the speaker (93). Press the press switch (61) to change
to a re siren in low volume with the ashing red light indicator (LED 69). Try turning the LED (69) around in the circuit.
Notice that the LED (69) still ashes and sound is heard from the speaker (93). This is because the speaker (93) does
not have polarity, meaning current can ow through it in either direction for it to make sound.
73. No Touch Special Effects
Replace the press switch (61) with the reed switch (83), then press the switch (62). You will hear the far away siren from
the speaker (93) while the red light turns on from the LED (69). Move the magnet (7) towards the reed switch (83) to
change sound effect without touching the circuit.
1st level
2nd level
1st level