Monday, February 2, 2009

LED Night Light

HI I'm back again this time with a simple review of a night light.  There are many forms of night lights available on the market either using incandescent bulbs or LEDs, with a manual switch or ones using light sensors which switches on automatically once the room or area is dark.  I've been searching for a night light which is cheap but yet reliable.Cheap, there are many available in two dollar shops.  But most of them are the incandescent type and once the bulb fuses its almost impossible to replace the bulb.  Moreover I didn't like the look of most of them.  

So I came across this version which uses five white LEDS and comes with a manual switch and runs straight from a 240volts mains supply.  So Just plug it in and switch on.  I bought this night light from Carrefour for RM5.10 (US1.40)!  I think thats really cheap.

What got me thinking was that LEDS worked from 2-3volts DC from 20mA upwards.  So how did they create a night light in such a small package without a step down transformer?  Well the answer is in the picture below.  Just resistors and capacitors will do the job.

I was still puzzled as to how it really all worked.  Did some searching on the Internet and I found this great website.

It basically explains and shows how you can build a circuit to run your LEDs of 240volts and you can see from the circuit diagram from the website that its basically the same as this night light being reviewed.

I don't know how long the page or site will be up there, so I decided to save it on my hard disk.  For all you people who are unable to find a cheap night light and would like to DIY, hope the info in the above mentioned website was useful.  

Well this is the inside of the night light.  Simple isn't it.

As you can see there is nothing much to it but just a couple of LEDs, diodes, capacitors, resistors and a switch. The magic to all this is the BIG RED capacitor which does all the work of bringing down the voltage for the LEDs. Here's a close up of the components.