Elenco 130-in-1 Electronics Playground - Manual (Page 76)

-76-
Here’s a variant of the last project. This time we use
an R-S flip-flop made with transistors and a NAND
multivibrator.
You will hear a sound in the earphone when you set
the switch to B and press the key. No matter how
many times you press the key you can still hear the
sound. The sound will stop when you set the switch
to A and press the key.
Compare the operation of this experiment with the
last one. What makes them independent from each
other? Are you able to think of some situations where
one circuit might be better suited than the other? Be
sure to make some notes about what you are
learning.
Notes:
EXPERIMENT #59: ANOTHER SET/RESET BUZZER
Wiring Sequence:
o 13-49-42-45-138
o 14-119
o 81-32-41
o 33-59-60-62-36-121
o 44-35-51-84
o 40-133-83
o 82-43-131
o 50-77-109
o 54-53-52-75-78
o 132-137
o 110-76-57-56-55-EARPHONE
o 58-EARPHONE
o 13-14 (POWER)
Schematic
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In this experiment you will make a push/pull, square
wave oscillator. This oscillator is known a push/pull
because it uses two transistors that are connected
to each other. They take turns maneuvering so that
while one transistor is “pushing,” the other is “pulling.
This type of oscillator is called a square wave
oscillator because the electrical waveform of the
signal has a square shape.
Slide the switch to position A to turn on the power
after wiring the circuit. We will be using square wave
signals in later projects therefore, note the sound
from the speaker.
Notes:
EXPERIMENT #67: PUSHING & PULLING OSCILLATOR
Wiring Sequence:
o 1-29
o 2-30
o 3-83-101-41
o 4-131
o 5-81-102-44
o 40-82
o 45-42-119
o 43-84
o 120-132
Schematic