In this we learn how to make a simple lED tubelight using a transformer based power supply, and by connecting the desired number of LEDs in series parallel connection.
Using white LEDs for illuminating our homes is becoming popular nowadays, due to the high power efficiency involved with these devices.
The diagram shows a straightforward configuration involving many LEDs, arranged in series and parallel.
Referring to the shown LED tube light circuit using transformer we see the LEDs are driven by a general purpose 24 V power supply for illuminating the LED bank very brightly.
The power supply incorporates standard bridge and capacitor network for the required rectification and filtration of the supply voltage to the LEDs.
The arrangement of the LEDs is done in the following way:
The supply voltage being 24, dividing it by the forward voltage of a white LED which is around 3 volts gives 24/3 = 6, meaning the supply voltage will be able to support at the most 6 LEDs in series.
However since we are interested to include many LEDs (132 here), we need to connect many of these series connected strings of LED through parallel connections.
That's exactly what we do here.
Total 22 strings of LEDs having 6 in each are connected in parallel, as shown in the figure.
Since current limiting becomes an important issue with the white LEDs, a limiting resistor is added in series with each of the strings. The value of the resistor may be optimized by the user for adjusting the overall illumination of the LED tube light.
The proposed design will provide enough light for illuminating a small 10 by 10 room brightly, and will consume not more than 0.02 * 22 = 0.44 Amps or 0.44 * 24 = 10.56 watts of power.
24 Volt, LED Tube Light Circuit Using Transformer, Circuit Diagram