This circuit produces short duration in an LED, from a power supply of only 1.5 V. The main feature of this circuit is the low consumption that guarantees a good durability of many months for a "button" type battery which takes the project ideal for feeding effects of models such as., for example, the lights of model aircraft or the signaling of a spaceship in plastimodelism.
The blinking frequency depends on the only external component of the design that is the capacitor C1. Its value can be between 22 and 470 uF. The LED is red common and its polarity must be observed.
In figure 1 we have the complete diagram of the flasher.
If the reader is skilful and has a fine-tipped iron for welding, you can use a DIL socket as a chassis and solder the LED and capacitor directly on this part as shown in figure 2.
For power supply we can use batteries of 1.5 or 1.3 V of any size and switch S1 is optional. The batteries do not need support, since it is not very common to find supports for a unit. The connecting wires, observing the polarity can be soldered directly on the battery.
MATERIAL LIST
Semiconductors:
Cl-1 - LM3909 - NATIONAL Integrated Circuit
LED1 - Common red LED
Several:
S1 – On/Off switch
C1 - 220 uF x 3 V or more - electrolytic capacitor
B1 - 1,5 V - 1 battery of any type or size
Socket for the integrated, wires, solder, etc.
