Shows how capacitors store Farads of energy. Note that farads represent a ratio of 1 Coulomb / 1 volt of electricity. or 1 F = 1 C / 1 E.
Try the different switches to see how the larger the farad value, the longer the LED stays on.
From Wikipedia:
"1 C = 1 F x 1V
It is equivalent to the charge of approximately 6.241×1018 (1.036×10−5 mol) protons, and −1 C is equivalent to the charge of about 6.241×1018 electrons."
The switch transfers power draw from the 9 volt battery to the 4 F capacitors (in parallel). They recharge every time main power is turned back on. A one farad capacitor can keep an LED on a long time.
Capacitors explain why you have to turn off your electronics for awhile in order to reset them. In older TVs, capacitors and vacuum tube transistors could cause potentially deadly shocks if serviced incorrectly. Notice how even when the switch turns off the main power, electrical potential remains.
