The principle and circuit of LED flashlight
Overview: The general problem of small flashlights is that the battery life is too short. According to statistics, an ordinary flashlight consumes about 2 watts of power. The power consumption of the LED flashlight as shown in the picture is only 24mW, and 4 AA alkaline batteries can provide more than 80 services (which means, can last for 1 month). Although the brightness of this flashlight is limited, it is It is sufficient for lighting on ordinary roads.
Working principle: The core of the LED flashlight is a 7555 time base integrated circuit (normal 555 cannot be used). A white LED (if you can’t find it, just replace it with another color) works at about 400mcd, so when focused, it can illuminate objects 30 meters away.
The way to focus is to install a short focal length focusing lens in front of the LED.
If other voltage values are desired, the value of resistor R3 must be modified: 9V – 470 ohms, 12V – 560 ohms
