2 LED Flasher with 555

The circuit is based on the IC1 that is 555, for the creation of alternate flashes from the two led D1-2, that can be also different colour. The frequency of alternation can be regulated from the trimmer R3 and from the C1, if changes his capacity. The supply can become from a battery or from one separate power supply. A use of circuit is creation '' clue '' of alarm. Exists the possibility is connected at the same time with D1-2, the optocoupler IC2-3, with that we externally drive circuits, for various uses.

Part List

R1-2= 1.5Kohm C2= 100nF 63V D1-2= LED 3mm
R3= 250Kohm trimmer C3= 100uF 16V BATT= 9V Battery
R4-5= 470 ohm IC1= 555 S1= Push Button or switch on-off
C1= 10uF 16V IC2-3= 4N25 optocoupler

The circuit described utilizes a 555 timer IC (IC1) configured in astable mode to produce a square wave output, which drives two light-emitting diodes (D1 and D2). These LEDs can be of different colors, providing visual indication through alternating flashes. The frequency of the flashing can be adjusted using a variable resistor (R3), which is a 250K ohm trimmer potentiometer, in combination with the timing capacitor (C1, 10uF). Adjusting the capacitance of C1 will directly influence the frequency of the output pulses.

The circuit can be powered by a 9V battery or an external power supply, allowing for flexibility in its application. The design can serve as an alarm indicator, where the alternating LEDs act as a visual cue for an alert condition.

Additionally, the circuit includes two optocouplers (IC2-3, 4N25), which can be connected in parallel with the LEDs. This feature allows the circuit to interface with other electronic systems or circuits, enabling the external control of various devices in response to the flashing LEDs. The use of optocouplers enhances the circuit's versatility, enabling it to drive higher power loads or isolated circuits without direct electrical connection.

The resistors (R1 and R2, each 1.5K ohm, and R4 and R5, each 470 ohm) are used to limit the current flowing through the LEDs, ensuring they operate within safe limits. The capacitor (C2, 100nF) provides additional stability in the timing circuit, while the larger capacitor (C3, 100uF) may serve as a power supply filter to ensure stable operation during transient conditions.

Overall, this circuit is a simple yet effective design for creating alternating LED signals, with the potential for integration into larger systems or applications requiring visual alerts. The circuit is based on the IC1 that is 555, for the creation of alternate flashes from the two led D1-2, that can be also different colour. The frequency of alternation can be regulated from the trimmer R3 and from the C1, if changes his capacity.

The supply can become from a battery or from one separate power supply. A use of circuit is creation '' clue '' of alarm. Exists the possibility is connected at the same time with D1-2, the optocoupler IC2-3, with that we externally drive circuits, for various uses. Part List R1-2= 1.5Kohm C2= 100nF 63V D1-2= LED 3mm R3= 250Kohm trimmer C3= 100uF 16V BATT= 9V Battery R4-5= 470 ohm IC1= 555 S1= Push Button or switch on-off C1= 10uF 16V IC2-3= 4N25 optocoupler 🔗 External reference