Long life energy-saving LED flashlight circuit

General problem is usually small flashlight battery life is too short. According to statistics, ordinary flashlight power consumption is about 2 watts. As shown in figure LED flashlight, the electricity consumption is only 4 24mW, 5 alkaline battery can provide more than 80 service (which means that the sustainable use of 1 months) although the brightness of this flashlight is very limited, but for ordinary when the road lighting is enough. The core of the LED flashlight is a 7555 time base integrated circuit (cannot be used with an ordinary 555). A white light emitting diode (if you can not find, can only be replaced with other colors) work when the brightness of about 400mcd, so that when the focus, you can illuminate the object 30 meters away. The focus is to install a short focal length lens in front of the LED. If you want to use other resistance voltage value, the value of R3 must be modified: 9V ~ 470 euro 12V ~ 560 Euro

Source: CLII