Build Your Own Ultra Bright LED Lamp Circuit

Description

This exceptionally bright white LED lamp operates on 230V AC with minimal energy consumption. It is suitable for illuminating VU meters, SWR meters, and other applications. High-quality LEDs available commercially range in price from Rs 8 to Rs 15. These LEDs produce a 1000-6000 mCd brilliant white light, resembling a welding arc, and function at 3 volts and 10 mA. Their maximum operating voltage is 3.6 volts, and the current capacity is 25 mA. Strict anti-static procedures must be followed when handling these LEDs.

Integrated Circuits: The circuit employs integrated circuits for enhanced functionality and protection. Specifically, a Zener diode is utilized at the output section to mitigate excessive reverse voltage levels across the LEDs during the negative half-cycle. These integrated circuits offer precise control and safeguard the LEDs from damaging voltage fluctuations.

Zener Diode

A Zener diode is a semiconductor device that allows current to flow in only one direction when the voltage across it reaches a specific breakdown voltage (zener voltage). In this circuit, it protects the LEDs by limiting the reverse voltage, preventing damage and ensuring consistent performance. It operates at 48V and 1W.

The circuit utilizes integrated circuits to control current flow and provide protection. A series resistor is implemented for limiting the current through the LEDs when operating with mains voltage. Without a resistor, the limiting resistor would dissipate approximately 2 to 3 watts of power, while a capacitor would not dissipate any power. The capacitance value is determined by the following formulas:

Where XC denotes capacitive reactance in ohms, C represents capacitance in farads, I signifies the current through the LED in amperes, f is the mains frequency in Hz, and Vrms is the input mains voltage. The 100-ohm, 2W series resistor prevents substantial ‘inrush’ current during transient conditions. A MOV at the input prevents surges or spikes, protecting the entire circuit. The 390-kilo-ohm, ½-watt resistor functions as a bleeder to provide a discharge path for capacitor Cx when the mains supply is disconnected.

Circuit diagram:

Integrated Circuits: The circuit incorporates an integrated circuit to enhance performance. A Zener diode is strategically placed at the output section to mitigate excessive reverse voltage levels that might appear across the LEDs during the negative half-cycles. This integrated circuit ensures reliable operation by preventing voltage-related damage to the LEDs.

Zener Diode

The Zener diode operates at 48V and 1W.

The LEDs are connected in series to achieve desired luminance. A series configuration of 16 LEDs (Fig. 2) generates a luminance equivalent to a 12W bulb. Alternatively, utilizing two series configurations of 23 LEDs in parallel (total 46 LEDs as illustrated in Fig. 3) yields a light output comparable to a 35W bulb. A configuration of 15 LEDs is suitable for a table-lamp light. Diode D1 (1N4007) and capacitor C1 operate as rectifying and smoothing elements to deliver a DC voltage to the row of LEDs. For a 16-LED row, utilize Cx of 0.22 µF, 630V; C1 of 22 µF, 100V; and a zener of 48V, 1W. Similarly, for a 23+23 LED combination, employ Cx of 0.47 mF, 630V; C1 of 33 µF, 150V; and a zener of 69V, 1W. This circuit (inclusive of LEDs) costs between Rs 200 and Rs 400.