I want to do a string of LED lights that can use batteries. About 55 or so. The lights are 5MM blue. How can I work? Urgent urgent!!
If it is a general common blue LED working current is 20 mA, voltage of about 2.5V can be lit, the battery power can be used in parallel, the benefits of this connection is one of the damage does not influence the normal operation of other LED. And each LED string to a current limiting resistor, LED protection lamp, prolong life, calculation formula of the resistance for V / 0.02A=: voltage current resistance: 3V, battery powered =3 / 0.02=150. You want to supply 55 LED batteries to work together, the total current is up to 0.02x55=1.1A, i.e. 1AH (ah) capacity of the battery can work 1 hours or so.
You can use the 4~6V battery, through the 4W, 2~3 Europe (6V with 3 Euro, 4V with 2 Euro) current limiting resistor, to the LED lamp power supply. The parameters of each lamp are: 3V, 20MA, in parallel (polarity). If you don't quite understand, you can also ask a science and engineering student (preferably a teacher) to help.
55, it is blue, blue and white as the power is too large, large power consumption, even in parallel connection, the voltage of 3V certainly do not move with the battery, just to be able to provide 4.5V voltage, and three batteries of 5 words for a while no electricity, regulated power supply with advice, use parallel to, from the 3V voltage can be gradually increased, the brightness is just perfect, too high voltage lamp
