Decoration light

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• Introduction
• Circuit description
• Schematics diagram
• Construction
• Photos
• Parts
• End

Introduction

Before some time I was asked for creating decoration light for dance use. Light was meaned to be candle replacement. Biggest troubles was battery selecting, which must be very small and enough voltage for LEDs. For variant with 1 LED I selects 6V battery GP11A and for variant with three LEDs I choose 12V battery GP23A.

Circuit description

Circuit includes serially connected battery with resistor, switch and LED. Resistor 150R correspond to current 20mA, when LED has voltage 3V. Battery GP11A was not designed for permanent consumption, but I had not any troubles with heating. Voltage of battery goes continuously down and current and LED bright too. Diode will light for few hours.

Circuit with three LEDs is same except 3 more serially connected LEDs. I choose resistor 100R, where with diode voltage 3.2V remains 2.4V for resistor with fresh battery. Current will be 24mA. Voltage of course goes down, that current in the circuit is lower.

Schematics diagram

schematics in Eagle 5 format

schematics in Eagle 5 format

Construction

Because circuit is very simple, I didn't design PCB but I used a small piece of universal board. Parts are mounted from a top side. I didn't found battery case, that I made my own from old russian connector, where I put battery to the small railing from two hard wires and two contacts which connects battery contacts. One 10mm LED with diffuse casing doesn't bright too much. I realised later second variant with three high-bright 5mm LEDs with narrow flaring angle which are mounted horizontally and their light is dispersed with help of translucent side of decoration lamp. Finished board is glued in to the decoration lamp on the place for candle.

Photos

Parts

All parts, battery and universal board are available in a local parts store.

End

Circuit works to satisfaction of users. Mainly 3 LED version lights really enough.