Jan 232011

Capacitors look like mini water-towers but instead of water they hold electric charge. This circuit shows the effect that capacitor size has on the length of time that an LED will remain lit.

Build the circuit below. be careful to hook the capacitor up the right way! (negative stripe goes toward ground/negative rail)
specs:  9v,   470 Ohm resistor,   1000 uF capacitor, red LED


1)  What happens as you push the button, then let go?

2)  Disconnect the wire between the LED and ground rail (orange in picture above. This will cut power to the led.
Now press the button to charge the capacitor for a minute.  Place your multimeter on each leg of the  capacitor.  What happens?

3) Fill in the table below

Capacitor value  (uF) Time it takes to drain the LED
100    uF _____________ seconds
1000  uF _____________ seconds
4700  uF _____________ seconds
 Posted by at 11:17 pm

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