Thursday, January 19, 2012

12v or 5v whats safer



I wish to implement small LED lamps to each room to yield smallest lighting in the eventuality of a appetite disaster a unchanging thing in the nation . My 12vDC complement runs off a UPS, so was meditative that utilizing LEDs the most appropriate choice due to the small stream they draw.

I have found a internal source of small 4 LED tuber lights typically used in cupboards, Aparate Foto list etc that supply sufficient light for me to see my approach around in the dark. They are powered with 3 small AAA batteries 1.5v each .

My meditative is to reinstate the batteries with an on/off switch continuous to my 12v supply and a 7805 regulator to dump the appetite to 5v.

Which of the following would you cruise the safer choice in conditions of electric wires feverishness / intensity repairs / danger, etc , deliberation the electric wires will be utilizing from my supply to each room by the roof

A. run the 12v from supply to the room, afterwards have a wall mountain box containing the 7805 and on / off switch one box in each room , or
B. have a singular 7805 at the supply source location, and run 5v to each room with usually the on / off switch the wall mountain box ?

Also, for the 7805, I have review opposing report

1. that the 7805 can be used as is to dump the 12v to 5v,
2. that one should supplement 2 capacitors to the stepdown circuit.

Which is the scold process ?





Pesonally, I would bond the LEDs in fibre of 4 or 5 with a stream extent resistor and run them from 12V if that is an option.






DaveO if you are utilizing a UPS, try not to rubbish stream whilst you do a voltage conversion. Depending on the stream used, the 7805 will rubbish appetite producing heat.




could run them off 200 volts if you chose to not recommended. Personally Id handle 3 in array with twelve volts and a not as big resistor it would make make make make make make use of of of of of of the same volume of physical phenomenon for 3* the light . Buying small 5mm high liughtness LEDs is poor in some-more aged to the bid concerned in positioning and electric wires them. They can be had for pennies every on ebay. Running 1 LED from 12V is no some-more greedy than utilizing a 7805 to step down the voltage.

Carefully cavalcade a 5mm hole so as not to repairs the aspect where you wish the LED and hang a singular LED in the hole from the behind and hold in place with blutack/tape/hot melt/whatever and the hardly noticable unless the on and dim in the room.





White LEDs typically have a brazen voltage of 3.5 volts so you cant make make make make make make use of of of of of of some-more than 3 in array on 12V. If they are utilizing the same stream utilizing 3 with make make make make make make use of of of of of of the same volume of extract as 1 utilizing a array resistor, the higher worth resistor to make make make make make make use of of of of of of 1 will rubbish some-more as heat. The 7805 will rubbish the stepdown voltage as heat.



Using these that are flattering standard Id make make make make make make use of of of of of of a singular 70 ohm resistor with 3 in array or a 470 ohm if usually utilizing 1 with 12V. Using a 7805 is a rubbish of money.



Got multiform thoughts going on above. Ill usually criticism on one.

If you are seeking to preserve energy, than twenty-three ultrabright white LEDS, able of 15,000mCD on usually 20mA, are the approach to go.
Heck, usually make make make make make make use of of of of of of 1 even, with a diffuser over it. I put 3 in a scoring appurtenance in array from 12V, had to dial the stream down to usually twenty-three mA since it was so damn bright!
Someone in Australia ed about removing these not long ago for really small money, less than the 43 cents USD each that I paid for them.



Yes and Yes.
Keep the stream underneath 20mA thogo with 82 ohm to start.