Elenco Upgrade Kit SC500 to SC750 - Manual (Page 130)

-41-
Project #PC29
Transistor Fading Siren PC
OBJECTIVE: To build a siren that slowly fades away.
Build the circuit shown. If continuing from the previous experiment
then close the Winscope program and run it again, to reset the
settings. Set Winscope to the settings shown on the right. Click
on the On-Line button to activate, turn on the switch, and press the
press switch (snap part S2). You hear a siren that slowly fades
away.
This display shows the siren just after pressing the press switch.
Settings
This display (at the same settings)
shows the siren when it has almost
faded out.
The waveform has
become weak and sometimes
erratic.
Turn on FFT mode to look at the frequency spectrum, try the
settings shown here. The display on the left shows the signal just
after pressing the press switch and on the right shows it just before
it fades out.
Settings
Modify the circuit in PC29 by replacing the alarm IC (U2) with the
music IC (U1), use a 1-snap and a 2-snap to make a connection
across D6-E6 on top of the music IC. The music slowly fades away
and stops. Use the same settings as in PC29 to view the waveform
and frequency spectrum.
Project #PC30
Fading Doorbell PC