Elenco Snap Circuits SOUND &reg - Manual (Page 83)

Transistor Audio
Amplifier
Build the circuit with the speaker (SP2) connected
using the red & black jumper wires. Set the
adjustable resistor (RV) to mid-range, and turn on
the slide switch (S1). Hold the speaker next to your
ear and blow into the microphone (X1), or talk
directly into it with your mouth close to it.
This circuit amplifies your voice and plays it on the
speaker. It should be easy to hear the blowing, but it
may be difficult to understand your voice, because
there isn’t enough amplification and there will be
some distortion. Also, the sound from the speaker
may not be as loud as hearing your voice directly.
If you have headphones (not included),
then modify the preceding circuit to match
this one, and connect your headphones to
the audio jack (JA). Set the adjustable
resistor (RV) to mid-range, and set the
500k
W adjustable resistor (RV3) for most
comfortable sound level (turn to the left for
higher volume, most of RV3’s range will be
very low volume). Turn on the slide switch
(S1). Blow into the microphone (X1), or talk
directly into it with your mouth close to it.
The sound may not be very loud.
Headphones
(not included)
WARNING: Headphones performance varies, so use caution. Start with
low volume, then carefully increase to a comfortable level. Permanent
hearing loss may result from long-term exposure to sound at high volumes.
!
Project 182
Transistor Audio
Amplifier (II)
Project 183
With headphones it may be
easier to recognize the
difference between the
circuit sound and hearing
your voice directly, than it
had been with the speaker.
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