Manual

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Did you know that a transistor alters its
characteristics according to the temperature? This
e
xperiment will show you how temperature affects
t
ransistor action.
View the schematic. The NPN transistor acts as a
pulse oscillator. The 22k
W resistor and the PNP
transistor control the voltage applied to its base.
The transistor’s base current and collector current
vary with the temperature.
Build this experiment and you will hear a sound from
the speaker. Modify the 50k
W control so that the
sound is low or a series of pulses.
Hold the PNP transistor between your fingers to
warm it up. As the transistor temperature increases
you will hear the tone become higher.
Notes:
EXPERIMENT #65: HEAT-SENSITIVE OSCILLATOR
Schematic
Wiring Sequence:
o 1-29
o 2-30
o 3-101-103
o 4-26-41-119
o 5-47-104
o 27-81
o 120-28-48
o 40-82
o 42-85
o 46-102-86
EP-130_62315RevC.qxp_EP-130_062812 6/23/15 11:17 AM Page 83