Elenco Electronics 202 - Manual (Page 96)

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Project #224
OBJECTIVE: To build a complete, working AM radio with
transistor output.
When you turn on the slide switch (S1), the integrated circuit (U5)
should amplify and detect the AM radio waves. Tune the variable
capacitor (CV) to the desirable station. Set the adjustable resistor (RV)
for the best sound. The two transistors (Q1 & Q2) drive the speaker
(SP) to complete the radio. The radio will not be very loud.
AM Radio with Transistors
Project #222 Mail Notifying Electronic Bell
OBJECTIVE: To build a circuit to
indicate if you have mail by
sounding a tone.
OBJECTIVE: To build a circuit to
indicate if you have mail by activating
the lamp.
Replace the speaker (SP) with the 6V
lamp (L2). When there is mail, the light
is blocked from the photoresistor (RP)
and the lamp lights up.
Turn on the slide switch (S1). If there
is enough light on the photoresistor
(RP), the speaker (SP) will not make
any sound. Place your finger over the
photoresistor and now the speaker
sounds. The sound will stay on until
you turn off the switch. A simple mail
notifying system can be made using
this circuit. Install the photoresistor
and the green LED (D2) inside the
mailbox facing each other. When
there is mail, the light is blocked from
the photoresistor and the speaker
turns on.
Project #223
Mail Notifying
Electronic Lamp