Why should a bright flashlight use a 3.7V battery, and why not?
High voltage lithium battery, the working voltage of 3.7V, and the driving voltage of LED is about 3.3V, and the driven part of the pressure drop, a lithium battery just right. If the dry battery, NiMH, requires 3 day series, if you want a single 1.5V driver LED to boost driver, boost large current driving cost is high, and the copycat flashlight, in order to reduce costs, with the current limiting resistor in series, the voltage of the battery must be higher than the working voltage of LED.The rest is the inherent characteristics of lithium battery, high energy, light weight a lot.
At present, in addition to LED light source, bright flashlight, as well as special lighting HID xenon torch, such as the current domestic brands have CSH-X01/02 (uscamel) design and manufacture of a series of super light flashlight. Strong light flashlight is a new type of lighting tool which uses LED as light source. It has the advantages of saving electricity, durability and brightness. Common light flashlight is a kind of outdoor lighting tool which uses high-power light-emitting diode as light source. It has the advantages of electricity saving, durability and high brightness. Cap LED flashlight with two light, a condensing cup condenser, a convex lens, condensing cup condensing effect is good, the light loss is small, light weight, can put the lamp holder part of the seal is very strict, improve the waterproof effect, the spot is in want of perfection is not adjustable, so that the use of it is near the illuminated area is very small, but the biggest advantage of stepless convex lens is the spot size can be adjusted, but it is difficult to achieve good waterproof, so the general outdoor sports enthusiasts will choose the former according to the environment. Power flashlight for rechargeable lithium ion batteries or nickel cadmium battery capacity, rated voltage 3.7V, ranging from hundreds to thousands of Ma, according to the common power source LED, endurance range in tens of minutes to several hours.
The use of nominal 3.7V lithium battery electric drive circuit for the lithium battery, Ni MH battery nominal 1.2V does not light, the voltage difference is too much, but also have the same led core using AA battery circuit but not the same, AA Battery LED flashlight driving circuit is a boost circuit, the voltage up to led Vf the above can only be lit
