How to create Circuit of Dual LED Flasher

 This circuit uses a one-gate oscillator, with a 4093 CMOS lG, to produce a

50% duty-cycle flasher in two LEDs or a bi-color LED. The circuit can be

powered by a 3 to 12-volt power supply and is useful in several experiments

and practical applications.You can use it as part of alarms, warning systems,

games, toys, and some scientific experiments, as we will describe here'

R2 and R3 values depend upon the power supply voltage, according to the

following table:

  Power Supply          R2, R3

3 Volts                       220 ohms

5 Volts                      330 ohms

6 Volts                      470 ohms

9 Volts                      820 ohms

12 Volts                   1,000 ohms

For more output you can use a transistorized output stage driving incandescent lamps. Experiments to observe light etfects on animals and plants can

be conducted with this circuit.

Pl and C1 determine flash rate. Flash rate can be adiusted by P1, but Cl

also can be altered in a large range of values, according to the application

you intend for the device.

Schematic diagram for the Dual-Led Flasher is shown in Figure 1. One gate

of a 4093 lC is used as oscillator and the other two are used as inverters.

Components placement on a PC board is shown in Figure 2.You can also

use a breadboard or solderless board to mount it as an experimental circuit.

Position of the polarized pieces, such as LEDs, eletrolytics and lC, should be

observed.

Parts List - Dual-Led Flasher

lC1 - 40938 CMOS integrated circuit

LED1 - bi-color or red and green common LEDs

(Radio Shack 276-012l

R1 - 100,000 ohm, 114W,5% resistor

R2, 3 - resistor according to power supply voltage - see text

P1 - 1,000,000 ohm potentiometer

C1 - 1 uF, 25 WVDC electrolyticapacitor