Only 3 components are used to make an LED flash at a speed determined by the value of capacitor C1. The circuit consumes an extremely small current, of the order of a few microampers, which makes the battery very durable. This circuit can be used in toys, decoration objects and signs.
Power is supplied with only 1.5 V from a standard battery or button. The circuit operates from 1.1 V which allows the use of alternative sources of energy.
The basis of the circuit is the integrated LM3909 (check availability at your component supplier) which is intended to excite LEDs from very low voltage sources. In figure 1 we have the complete diagram of the light pulser.
In figure 2 we have the assembly in a small printed circuit board. The circuit can also be mounted on a protoboard.
Material list
CI-1 - LM3909 - Integrated Circuit
LED - Common Red LED
B1- 1.5 V - battery - see text
C1- 220 uF x 3 V or more - electrolytic capacitor
Miscellaneous: printed circuit board, wires, soldering, etc.
