Components
small jumper wires
9V battery
breadboard
1N4007 Diode
10000uF capacitor
330 ohm resistor
push button
Push button is held for 15 seconds. When released the LED is charged by the 10000uF (0.01F).
t =RC = 330 ohm x 0.01F = 3.3 seconds
t = 5RC (63.9%) =5 x 330 ohm x 0.01F = 16.5 seconds