Introduction: Ambient Light Powered LED Flasher

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About: Music: my profession for over 40 years... Electronics: my beloved hobby always.

This LED flasher circuit is optimized to run from the ambient light present in your room and no other power source. A small photovoltaic cell converts the light to electricity and that weak current charges a 1000uF capacitor. After a time period of around 1.5 seconds, the stored energy is discharged through an LED.

Step 1: Overview

Step 2: Circuit Diagram & Main Components

FV cell: should deliver at least 2.5v (no load open circuit) and 0.5mA short circuit current (under room lighting)

Incandescent / halogen lighting is the most efficient for F.V.cells (after daylight) and fluorescent is the least.

Q1-Q2: BC549 npn transistors

Q3: 2N7000 N-channel mosfet. You may have to select it for lowest gate threshold voltage or use a low threshold BSH103

LED: use a high efficiencyred LED . (red LEDs have the lowest forward voltage (Vf) )

Step 3: Photovoltaic Cell

Step 4: LED

Step 5: Capacitor

Step 6: Astable Multivibrator

Step 7: FET

Step 8: Watch the Video - Thank You !