Elenco Upgrade Kit SC100 to SC750 - Manual (Page 9)

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Project #102
OBJECTIVE: To show the increase in voltage when batteries are
connected in series.
When you turn on the slide switch (S1), current flows from the
batteries through the slide switch, the 100
Ω resistor (R1), the LED
(D1), through the LED (D2), and back to the second group of batteries
(B1). Notice how both LED’s are lit. The voltage is high enough to turn
on both LED’s when the batteries are connected in series. If only one
set of batteries is used, the LED’s will not light up.
Some devices use only one 1.5 volt battery, but they make hundreds
of volts electronically from this small source. A flash camera is an
example of this.
Batteries in Series
Project #103
OBJECTIVE: To make fun sounds using light.
Build the circuit as shown, and turn on the slide switch (S1). Vary the
amount of light to the photoresistor (RP) by partially covering it with
your hand. You can make screeching sounds by allowing just a little
light to reach the photoresistor.
If you replace the 10
μF capacitor (C3) with a 3-snap wire or any of the
other capacitors (C1, C2, C4, or C5), then the sound will be a little
different.
Ticking Screecher
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