Manual

-132-
T
his AM radio station circuit lets you actually
transmit your voice through the air.
When you completed wiring the circuit, tune your
AM radio a weak station or place with no stations.
Place the AM radio close to the circuit since the
signal can only transmitted a few feet. As you talk
into the speaker adjust the tuning capacitor, until
you hear your voice on the radio
The audio signals produced as you talk into the
speaker are amplified by transistor Q1. These
signals control the amplitude of the RF oscillator
signal. The antenna and tuning capacitor tune the
RF signal to the setting on your AM radio dial and it
is transmitted through the antenna.
The amplitude of the RF signal is controlled by
transistor Q2. The RF signal is amplified by NPN
transistor (part of the RF oscillator) before the AF
(audio frequency) signal modulates it.
N
otes:
EXPERIMENT #111: AM RADIO STATION
Wiring Sequence:
o 1-29
o 2-30
o 3-111
o 5-7-90-42-119
o 6-12-47-ANT
o 8-11-99
o 40-112-94
o 41-43-93-78
o 77-44-131
o 45-79
o 89-100-46
o 48-80
o 121-122
o 124-132
Schematic
Note: The ANT is the 3-meter long
green wire. Connect the one end
of the wire to the spring and
hang the wire up vertically.
EP-130_62315RevC.qxp_EP-130_062812 6/23/15 11:18 AM Page 132