Simple LED Flasher Circuit Using LM3909 Oscillator IC

LED Flasher Circuit, here, uses LM3909 as the main operator. It is a very simple, cost-effective circuit that uses just an IC LM3909, an LED, and an electrolytic capacitor. The IC LM3909 operates at a very low voltage of 1.5V and outputs a bright high current LED pulse that makes up the LED flasher circuit.

Hardware Components

The following components are required to make LED Flasher Circuit

S.no	Component	Value	Qty
1.	IC	LM3909	1
2.	LED	–	1
3.	Electrolytic Capacitor	100µF/16V	1
4.	Battery	1.5V	1
5.	Breadboard	–	1
6.	Connecting Wires	–	1

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LM3909 Pinout

For a detailed description of pinout, dimension features, and specifications download the datasheet of LM3909

LED Flasher Circuit

Working Explanation

The IC LM3909 is an oscillator IC designed to flash Light Emitting Diode. The circuit is such that it requires only a capacitor and battery in addition to the IC and hence, is self-starting inherently. Moreover, even with the operating voltage of 1.5V, it is capable of delivering 2 or more Volts of pulses to the LED. This voltage boost in the circuit is done by the Electrolytic capacitor of 100µF.

Application

• Locating boat mooring as well as finding flashlights in the dark
• Emergency locators
• Electronic circuits such as sawtooth generators or trigger circuits.
• Toys and decorations
• Warning indicators