Elenco Electronics EP-130, Manual

Page: 82 / 160

In this project we will make a push/pull, square wave
oscillator. This oscillator is called a push/pull
because it uses two transistors that are connected
to each other. They take turns operating so that
while one transistor is “pushing,” the other is
“pulling.” Scientists study waveform patterns to help
understand electronic signals – such as the signal
produced by the current in this project. A square
wave oscillator produces waves that look like
squares.
After wiring the circuit, slide the switch to position A
to turn on the power. Note the sound from the
speaker, because we will be using square wave
signals in later projects.
This oscillator circuit works well with low DC voltage
supplies. For this reason, scientist and technicians
use DC to AC converters and DC to DC inverters
with supply voltages of about 0.5 to 12 volts.
Another characteristic of this oscillator is that it
makes a maximum use of the transformer. The
circuit produces the maximum power for the
particular size transformer that is used.
Notes:
EXPERIMENT #64: PUSH/PULL SQUARE WAVE 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
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Schematic