Easy

Capacitor Charge/Discharge LED Fader

No chip at all: a large capacitor charging and discharging through a resistor makes an LED fade in and out smoothly, like a "breathing" light — purely analog.

Circuit Diagram

+9V 47K LED C 10000uF discharge button Large C charges through R → LED fades in; button discharges it instantly

How to Build It

  1. Connect a large electrolytic capacitor in series with a resistor and an LED, between the positive rail and GND.
  2. Connect a push button in parallel with the capacitor, to discharge it quickly when pressed.
  3. Power the circuit — the LED will light up gradually as the capacitor charges.
  4. Press the button — the LED turns off instantly (the capacitor discharges).
  5. Release the button — the LED lights up gradually again.

Bill of Materials

ProductCodeQty
Actuation push button H570033 1
Capacitor (electrolytic/ceramic/SMD/film) GT2A109M35100SB 1
LED (3/5/10mm, SMD, power) l-934ID-12V 1
Resistor DR47K-8/9 1
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