Schematic Diagram

1. This makes it possible for a charge of 3 mAh to be available after a 10 minute ride, 1.e., enough for the E light to flash for about4 minutes after the bicycle is halted. A ! relay is used to switch between operation while riding and while standing still.
2. The circuit is essentially composed of a battery charger and a logic switching section. The NiCd battery is charged from a I voltage doubler C1-Cz-Di—Dz—C to ensure a charge current of about 20 mA when riding at a reasonable speed.
3. Whén the dlI9CI Y voltage drops below approximately 2XL N1 switches on multivibrator Nz—Na-N4 which causes the relay to toggle at a rate determined by R4-Ca
4. Of course, due care must be taken to avoid the battery con- tacts touching the metal inside of the light.
5. Since Ca is only slowly discharged via R1, N4 remains enabled for about 4 minutes after halting.
6. When the bicycle is in motion, the voltage from the dynamo, G, ensures that N4 is enabled, so that T1 actuates Re, and the small 6 V bulb is illuminated.
7. Push- button S1 enables immediately switching off the rear light, because R2 then discharges Ca in a few seconds. Gate N1 monitors the dynamo voltage, which is rectified by Da-C4-Rs.
8. The 5V DIL relay requires only llmA, while the current consumption of the 4093 is virtually negligible at about l nA. 

Bicycle Turn Signal Flasher Circuit Diagram