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179. Four sounds
Assemble the circuit as shown in the illustration. Close switch
15
to turn it ON. You'll hear the
first sound. First close the button 14, then the reed switch
13
(using a magnet), and shield the
phototransistor
132
from light to activate three more sounds. In this circuit, the kind of sound
you generate doesn't depend on how bright the light is that shines on the phototransistor. All it
does is activate one of the sirens. To hear the sound produced when you close reed switch 13,
you have to shield
phototransistor 132
from the light.
180. Four sounds 2
Connect reed switch
13
to terminals A-B. Use a magnet to close the reed switch. Now you'll hear
a completely different sound when the B-F pins are closed.
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181. Light – Sound
Assemble the circuit as shown in the illustration. Close switch
15
to turn it ON. The LED
blink, but you won't hear a sound. Use a magnet to close reed switch 13. You'll hear the sound
of shots being fired from the loudspeaker in tune with the blinking of the LED.
182. Light – Sound 2
13
14
Replace reed switch
with button
it will now serve as the connection to the loudspeaker
20. Replace button
14
with light-bulb
18
– now when the power is turned on, the LED will light
up at that same time the sound is heard, while the lamp barely flickers (this is because a much
larger current than that produced by the LED is required to activate the lamp). Replace light-bulb
18
with electric motor
24
– now when you turn on the power, at one and the same time, the
LED lights up and sound is heard, while the motor is activated in time with them.
183. Light – Sound 3
17
will
Assemble the circuit as shown in the illustration. Replace the LED
17
Now, when you close switch
15
turning it ON, you'll hear a sound from the loudspeaker, but the
LED won't light up. Use the magnet to close reed switch
13
– the led will start flashing.
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with the loudspeaker 20.
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