Elenco Circuit Maker Sound Plus 200 - Manual (Page 46)

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Project #92 Capacitor Photo Control
Turn on the slide switch (S1) and press the press switch (S2). If there is
light on the photoresistor (RP), then the LED (D1) will stay on for a few
seconds after you release the press switch.
Project #93 Capacitor Control
Build the circuit and turn on the slide switch (S1). The LED (D1) is bright
but slowly gets dark as the 100mF capacitor (C4) charges up.
The LED will stay dark until you press the press switch (S2), which
discharges the capacitor.
The energy stored in the 100mF capacitor (C4)
keeps the controlling current to the NPN
transistor (Q2) on even though the press
switch was turned off. If it is dark, the high
resistance of the photoresistor shuts off the
current to the transistor.
CM-200_Manual_031914.qxp_CM-200_Manual_031914 4/2/14 12:04 PM Page 46