LM3909 Datasheet, PDF (5/8 Pages) National Semiconductor (TI) – LM3909 LED Flasher/Oscillator

Typical Applications (Continued) (See applications notes above)
Flashlight Finder
Note LM3909 capacitor and LED are installed in a white translucent cap on the flashlight’s back end Only one
contact strip (in addition to the case connection) is needed for flasher power Drawing current through the bulb
simplifies wiring and causes negligible loss since bulb resistance cold is typically less than 2X
TL H 7969 – 10
4 Parallel LEDs
High Efficiency Parallel Circuit
TL H 7969 – 12
Note Nominal flash rate 1 3 Hz Average I_DRAIN e 2 mA
TL H 7969 – 13
Note Nominal flash rate 1 5 Hz Average I_DRAIN e 1 5 mA
5