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184. Fun sounds
Assemble the circuit as shown in the illustration.
Switch 15
is in the OFF position. Shield photot-
132
from the light. Briefly press button 14. Keep on pressing the button, making sure
ransistor
light is hitting the phototransistor. Close the switch to turn it ON. Change the intensity of the light
hitting the phototransistor.
185. Fun sounds 2
Swap
switch 15
and phototransistor 132. Press button 14, and also change the status of the switch
(ON/OFF) and the intensity of the light hitting the phototransistor.
186. Fun sounds 3
Remove switch 15. Connect
phototransistor 132
to the E-F pins. Close the B-G pins with wire 2.
Press button
14
and change the intensity of the light hitting phototransistor 132.
187. Motor sounds
Assemble the circuit as shown in the illustration. Switch
15
is in the OFF position. Swap button
14
and switch 15. Instead of loudspeaker 20, install electric motor 24. If you have long hair,
make sure that you don't get it caught in the rotor of the motor. Close the switch to turn it ON.
Gently tap your finger on top of the electric motor to stop it. Listen, the motor, although quietly, will
reproduce signals just like the loudspeaker did.
188. Lamp and LED power consumption
15
Assemble the circuit as shown in the illustration. Switch
is in the OFF position. Replace the wire
3
connected to terminal G with the light-bulb 18. Press button 14. The LED
17
the loudspeaker will emit sound, but the lamp won't light up. You see, to activate both the LED
and the sound circuit, there isn't enough current left over to turn on the lamp.
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189. Loud Morse Code
Assemble the circuit. Press button
14
briefly, and you will hear „Morse", as the Morse code is
sometimes called. To really convey words, you need to study the alphabet itself (see table). A very
short press on a button is a „dot", and a slightly longer press is a „dash". The duration of the dash
is three times the duration of the dot. There are 7 „dots" of silence between words.
190. Quiet Morse Code
Replace the speaker
20
with the piezoelectric speaker 11, now the sounds won't disturb anyone.
will light up and
The most famous Morse code signal in the world, which is still used today, is the SOS help signal.
Be sure to remember it and practice the transmission:
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