Micro Flasher

This micro flasher circuit continuously emits a flashing light while consuming very little power. The circuit can operate for an extended period using four 1.5V torch cells. A low-power CMOS IC, the CD4093 (IC1), is utilized to generate sharp pulses of 20 ms from a red LED. The LED appears to glow continuously due to the persistence of vision, resulting in significant power savings. IC1 is a quad NAND gate, with one gate configured to produce oscillations. The unused inputs are held at logic high by connecting them to the positive supply. The resistor R1 determines the charging current of capacitor C1.

The micro flasher circuit operates based on the principles of pulse generation and light persistence. The core component, the CD4093, is a versatile CMOS IC that contains four NAND gates. In this application, only one gate is employed to create an astable multivibrator configuration, which oscillates between high and low states, producing the desired pulse output.

The configuration involves connecting the output of the NAND gate to the anode of the red LED, while the cathode is connected to ground. The timing components, resistor R1 and capacitor C1, are crucial in determining the frequency of the output pulses. The resistor R1 controls the charging rate of the capacitor C1, thus influencing the duration of the high state of the output pulse. When the capacitor charges through R1, the voltage across it rises until it reaches a threshold that triggers the NAND gate to switch states, turning the LED on. Once the capacitor discharges, the cycle repeats, creating a flashing effect.

To ensure stable operation, the unused inputs of the NAND gate are connected to a logic high voltage, which prevents floating inputs that could lead to unpredictable behavior. The choice of four 1.5V torch cells as the power source provides a reliable and long-lasting supply, capable of sustaining the circuit's operation for extended periods without frequent battery changes.

This micro flasher circuit exemplifies an efficient design for applications requiring low power consumption while providing a visually appealing flashing light effect. It can be utilized in various applications, including decorative lighting, indicator lights, or as a simple teaching tool for understanding basic electronic components and circuit behavior.This micro flasher circuit continuously emits flashing light with the consumption of very less power. The circuit can run for a very long time for four 1. 5 V torch cells. Here a low power CMOS IC CD4093 (IC1) is used to produce sharp pulses of 20 ms from a red LED. The LED appears to be glowing continuously due to persistence of vision, and lot of p ower is saved. The IC1 is quad NAND gate whose one gate is used for producing oscillations. The unused inputs are kept to logic 1 by connecting it to the positive. The value of R1 determines the charging current of C1. 🔗 External reference