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Showing posts from April, 2015

Low Voltage DC Lighting

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12V DC & 24V DC LED lights LED Lights that can work off a Standard Car battery is an attractive proposition.  We have created a few designs on 12V as well as 24V DC.

It is important that LEDs are driven with a constant current.  An LED is a current driven device. That is it will light up to its given intensity when the rated current flows through it.  Its colour rendition will also be specified at that current.

Anything above or below the rated current two things will happen.
The intensity will change, as will be the efficacy i.e. lumens/wattThe Colour temperature will shift and you may not get the white light that you expect. What is the role of voltage?
Once you ensure a constant current (we will see how we can achieve that later), we can then measure the voltage across the terminals of the LED.  This voltage should be in a range specified by the manufacturer.  For White LEDs it is usually in the range of 2.9 to 3.5 Volts.  Whatever the current you deliver this voltage will remain…

Rail Stations to be LED lit

Virgin Trains: LED lighting at stations is as much about customer satisfaction as it is about energy.............Virgin is refraining from installing high levels of intelligent lighting system in which, for example platform lights would remain off when not needed, and turn on when sensors detect people on the platform, because such systems could confuse train drivers........Click the link to read more.

Solar Lighting for Rural & off-grid use

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Tata Power has started selling its PV products through snapdeal.
Here is the link to a product I have known for a while.

http://www.snapdeal.com/product/tata-venus-1-solar-home/1470961052

It is a robust system and should last years.  The light is of the CFL type. The lamp is actually a 4 Pin PL lamp which is more efficient than the traditional 2 pin variety.

A 4-Pin lamp uses a pre-heat technology for firing the lamp, and hence has a much longer life.  It also prevents blackening of the lamp at the electrode ends.