Spotlight! What's inside? How does it work?

Welcome back. I really got a good response for my first blog and here I am writing my second blog. From reading the title you already got an idea about what I'm going to discuss with you here today. Yes, LED spotlight. If you are from a non technical background I'll try to make it as simple as possible. But I have to discuss some technical terms which I cannot avoid. 

You might have seen the LED spotlights in your house, your friends' house or in shopping complexes, malls, coffee houses, exhibition halls etc. 

I'm writing this blog since one of the LED spotlights in our house had stopped working. As every parent, my dad gave it to me to repair it as I'm from electrical background. Can't help that! 

Let us discuss about our first question 

What's inside an LED spotlight?

To answer this question, let's see how it is constructed. 

It is made up of aluminium (or even plastic in some other spotlights) as it is resistant to corrosion. Fiber glass which allows beam from LEDs to converge and avoid dispersing the light. 

Here we can observe fin heat sink structure to dissipate heat generated by the LEDs.

This is how the circuit look when you open the case. To make easier, I'll show you how exactly the LEDs are connected.

The LEDs used here are surface mount LEDs. The yellow lines indicates the connection. You can see the positive and negative signs marked on board. The LEDs are connected in series i.e they are connected adjacent to one another.

Now our next question is 

How does it work?

To know this let us see the circuit diagram first. 

You can just open and zoom in if you can't see properly. 

Working: 

A 230V ac supply is given from the mains to the LED driver. An LED driver is a circuit that converts ac supply from mains to required dc output. In this case, the LED driver converts 230V ac to 10V dc. The voltage across each LEDs is 2.82V according to multimeter readings with some tolerant value. 

When the supply is given, the current through all the LEDs remains same but the voltage divides as it is a series connection. 

Here we give 10V dc and the voltage gets divided to each of the LEDs and the LEDs glow. 

The voltage for different coloured LEDs will be different and you can check using the data sheets available online. 

And that's all about this blog. 

WAIT! Did I repair that LED spotlight ? 

To know the answer please do comment. 

Till next time. Bye.