This is a nice demo circuit to build to see the effect that the capacitor adds to a circuit.
By using a capacitor, you add a time delay to your circuit so that your LED fades out instead of turning off right away after you release the button.
The Circuit
Without the capacitor, this circuit would be a simple light-switch circuit that turned the LED on and off with the push-button.
But since we have a capacitor in parallel with the resistor and LED, the LED will keep lighting for a little bit of time after the button disconnects it from the battery. Then it fades out as the capacitor discharges.
The bigger the capacitor, the longer the LED will remain lit after releasing the button.
Parts List
| Reference | Value |
|---|---|
| 9V | |
| C1 | 1000 µF |
| D1 | Light-Emitting Diode (any color) |
| R1 | 470 |
| SW1 | Pushbutton |
The Layout
Once you've connected the circuit, push the button to turn on the LED, then release the button to see the fading out effect.
PS! If your capacitor value is too low, you won't see the effect. Use a value of 1000 µF or more.
