Manual

-139-
T
his experiment is a simple transistor audio amplifier
used as an audio signal tracer. You can use this
a
mplifier to troubleshoot transistor audio equipment.
You can connect the wires to different terminals in
the circuit until you find the stage or component that
does not pass the signal along when a circuit is not
working correctly.
The 0.1mF input capacitor blocks DC so you can
probe around circuits without worrying about
damaging the circuit.
The amplifier circuit is a common-emitter type. The
transistor’s emitter is connected directly to the input
and the output of the earphone. Its base current is
the self-current type. The current from the transistor
collector provides current to the base (through the
470kW resistor). This provides some stabilizing
negative DC feedback.
You can use this amplifier to check any transistor
radio or amplifier you have that needs fixing.
N
otes:
EXPERIMENT #117: AUDIO SIGNAL HUNTER
Schematic
Wiring Sequence:
o 46-110-94
o 47-79-93-EARPHONE
o 124-48-PROBES
o 119-80-EARPHONE
o 109-PROBES
o 121-122
EP-130_62315RevC.qxp_EP-130_062812 6/23/15 11:18 AM Page 139