Elenco Snap Circuits® Deluxe Sound & Light Combo - Manual (Page 98)

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Build the circuit as shown, and connect your own
headphones (not included in this set) to the audio
jack (JA). Turn on the bottom slide switch (S1).
Talk into the microphone, and listen the echo on your
headphones. Set the 500kW 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), then adjust the amount of echo using the
lever on the adjustable resistor (RV); move the lever
up for more echo or down for less echo. Try this at
different RV settings, because the effects are very
interesting with both high and low echo amounts. Also
try it while saying different words/sounds.
Turn on the top slide switch to make the sound
louder, or turn it off to make the sound softer.
Project 193 Echo
Project 194 Echo with Headphones
Project 195
Louder Echo
with
Headphones
Headphones
(not included)
WARNING: Headphones performance
varies, so use caution. Start with low volume,
and then carefully increase to a comfortable
level. Permanent hearing loss may result from
long-term exposure to sound at high volumes.
!
Turning on the top slide switch
adds the 0.1mF capacitor (C2)
to the circuit, which increases
the amplification in the echo
IC. With headphones, the
sound can be made louder
because the microphone does
not pick it up easily.
Build the circuit as shown, and place it in a quiet
room. Connect the speaker (SP2) using the red &
black jumper wires, and then hold it away from the
microphone (X1). Turn on the slide switch (S1). Talk
into the microphone, and listen the echo on the
speaker. Adjust the amount of echo using the lever
on the adjustable resistor (RV); move the lever up
for more echo or down for less echo. Try this at
different RV settings, because the effects are very
interesting with both high and low echo amounts.
Also try it while saying different words/sounds.
Note: you must hold the speaker away from the
microphone or the circuit may self-oscillate due to
feedback. You also need a quiet room, with low
background noise.
Use the preceding circuit,
but replace the 0.1mF
capacitor (C2) with the 1mF
capacitor (C7). The sound is
louder now when both slide
switches (S1) are on.
If you hold your headphones
next to the microphone (X1),
you may hear a whining
sound, because the
headphones sound might be
picked up by the
microphone and be echoed
again and again and again.
If the speaker is too close to the
microphone, then the speaker’s sound
will be picked up by the microphone and
be echoed again and again and again,
until you can’t hear anything else. The
same thing can happen if the room is too
noisy, or if you talk too loud.
SCC-350_Manual_Part_B.qxp 7/25/14 2:06 PM Page 42