Efficient LED Blinker Design:
This LED blinker is ingeniously crafted with minimal components and is specifically designed to function within an AC supply range of 4–16 V (or 6–24 V DC). Its exceptional feature lies in its incredibly low current consumption, drawing less than 1 mA. This attribute renders it highly suitable for extended battery-powered usage. In comparison to the widely used 555 timer IC employed as an astable multivibrator. This LED blinker presents numerous advantages in diverse applications.
Adjustable Blinking Rate:
The blinking rate of this circuit can be fine-tuned, ranging from 1 to 1.5 Hz, based on the values of its timing components. Despite each blink’s brief duration, the LED achieves remarkable brightness due to the utilization of relatively high LED current. This feature makes the circuit versatile, finding applications in model railway systems, both in stationary setups and moving devices.
Simple Oscillation Mechanism:
An economical thyristor functions as the oscillator in this design. A voltage divider, composed of R1 and R2, maintains the gate lead’s voltage at approximately 20% of the supply voltage (G). Capacitor C2 charges via R3, lowering the cathode (K) voltage until it is slightly below the gate voltage. When this threshold is reached, the gate current becomes sufficient to trigger the thyristor, initiating the blink sequence.
Effective Blinking Control:
Following triggering, C2 discharges through the cathode-anode junction, R4, and the LED. R4’s role is to restrict the LED current within permissible limits. The cathode-anode junction is cut off again after C2 discharges, as the resistance of R3 prevents sustaining current levels from being reached. Subsequent blinks are delayed until C2 recharges. The circuit’s blinking rate can be modified extensively by adjusting the values of R3 and/or C2, offering flexibility in its applications.
Flexible Power Source:
The circuit can be powered using a variety of sources, including standard model railway or bell transformers. A half-wave rectifier coupled with a small filter capacitor is sufficient for rectifying the supply voltage. The components can be mounted on a compact printed circuit board or a perforated board. Additionally, the blinker can be powered by a DC source (ranging from 5 to 24 V), with reverse-polarity protection provided by D1 in such configurations.