Elenco Electronics 202 - Manual (Page 72)

-71-
Project #160
OBJECTIVE: To demonstrate how batteries can store electricity.
Build the circuit, then connect points Y & Z (use a 2-snap wire) for a
moment. Nothing appears to happen, but you just filled up the 470
μF
capacitor (C5) with electricity. Now disconnect Y & Z and instead touch
a connection between X & Y. The green light emitting diode (D2) will be
lit and then go out after a few seconds as the electricity you stored in it
is discharged through the diode and resistor (R2).
Notice that a capacitor is not very efficient at storing electricity -
compare how long the 470
μF kept the LED lit for with how your
batteries run all of your projects! That is because a capacitor stores
electrical energy while a battery stores chemical energy.
Make Your Own
Battery
OBJECTIVE: To demonstrate how batteries can store electricity. OBJECTIVE: To demonstrate how batteries can store electricity.
Now replace the 1k Ω resistor (R2) with the 100Ω resistor (R1) and try it.
The LED (D2) gets brighter but goes out faster because less resistance
allows the stored electricity to dissipate faster.
In the preceding circuit, replace the 470 μF capacitor (C5) with the
100 μF capacitor (C3) and repeat the test. You see that the LED goes
out faster, because the 100 μF capacitor does not store as much
electricity as the 470 μF.
Project #161
Make Your Own
Battery (II)
Project #162
Make Your Own
Battery (III)