Elenco Upgrade Kit SC300 to SC750 - Manual (Page 200)

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This recorder IC circuit works the same as in project PC40 except
that the power amplifer IC (U4) used here makes the sound much
louder than in project PC40. If viewed with the same Winscope
settings as in PC40, then the waveform appears as shown below.
The output from the recorder IC has not changed, but the flat
edges at the top and bottom of the waveform indicate that the
higher amplification is distorting the sound.
Flat edges
Project #PC42
Music Meter PC
OBJECTIVE: To show how high amplification can distort music.
Use the LOW (or 10mA) setting on the meter (M2). Set the
adjustable resistor (RV) to the bottom position and turn on the slide
switch (S1), you will see a waveform like that shown below. Set the
adjustable resistor to the top, and the waveform looks like that
shown on the bottom left, due to lower resistance in the circuit. A
sample frequency spectrum is also shown on the bottom right.
Settings