Elenco 130-in-1 Electronics Playground - Manual (Page 26)

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II. BASIC ELECTRONICS CIRCUITS
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Do you want to become an amateur radio ham?
Many radio operators started out using an oscillator
with a tone control like this one. Listening to the same
tone for a long time can be very tiring, so the tone
control in this experiment can be very helpful. Simply
connect the wires for this circuit and your code
practice oscillator is ready for use.
Morse Code is a code system that uses dots and
dashes, invented by Samuel Morse. The most
effective way to learn Morse Code is to find someone
else who is interested in learning the code. Set up a
schedule and practice every day. Create a progress
chart so you can see your improvement. Take turns
sending and receiving, and it won’t be long until the
code becomes almost like a spoken language.
Operating the key becomes automatic. It takes hard
work to get to this point, but you’ll be proud when you
do.
You can also use different tones to make up your own
special code.
If you want to practice by yourself simply use the
earphone. Disconnect the speaker and connect the
earphone to terminals 27 and 28. Now, the control
acts as a volume control as well as a tone control. If
you want a fixed tone and volume, just replace the
control with a fixed resistance.
When you adjust the control for less resistance, the
0.05
μF capacitor charges faster, making the
frequency (and the tone) higher. The opposite
situation occurs when the control is adjusted for more
resistance.
Notes:
EXPERIMENT #114: MORSE CODE OSCILLATOR WITH TONE CONTROL
Wiring Sequence:
o 1-29
o 2-30
o 3-87-105-109
o 4-124
o 5-41-110
o 85-106-40-27
o 28-88
o 86-42-137
o 119-138
o 121-122
Schematic