Elenco XP&trade - Manual (Page 25)

This circuit shows how a capacitor can store
and release electrical energy.
Turn on the slide switch (S1) for a few
seconds, then turn it off. The green LED (D2)
flashes dimly for a moment, and then goes
dark as the batteries (B3) charge up the
470
μ
F capacitor (C5). The capacitor is storing
electrical energy, as if it were a small battery.
Now press the press switch (S2) for a few
seconds. The red LED (D1) is initially bright
but goes dim as the capacitor discharges itself
through it.
The capacitor value (470
μ
F) sets how much
electricity can be stored in it, and the resistor
value (1k
Ω
) sets how quickly that electricity
can be stored or released.
Capacitor Battery Project A23
Turn on the slide (S1) and blow into the microphone (X1). The
red LED(D1) will flicker and you hear static from the speaker
(SP).
Talk loudly into the microphone. You can hear your voice on the
speaker, though it may be badly distorted.
Blow Off Sound Project A24
-24-
Capacitors store electricity in an electric
field between metal plates, with a small
separation between them. This electric
field is similar to the magnetic field of a
magnet. Compared to batteries (which
store energy as separated chemicals),
capacitors can only store small amounts
of energy, but they can release it quickly,
can be made in very small sizes, and are
inexpensive.