Emergency light circuit

Emergency light circuit using NPN transistors & 1W LED

Emergency light circuit  NPN

1W 300~350mA LED  (or multiple LEDs in parallel)
Cell phone Li-ion battery 3.7V
USB 5V power
S8050 NPN  20V 700mA transistor control LED current
Adjustable brightness
Charge current indicator LED
Minimum standby current

Emergency light circuit

Simplified version

Choice of R1 for LED
20mA  40k
40mA  20k
60mA  13.3k
80mA  10k
100mA 8k
200mA 4k
300mA 2.6k

Emergency light circuit PNP