This dimming controlled LED driver circuit is based on LM3409 P-channel MosFET (PFET) controller for step-down (buck) current regulator, which require few external electronic components and it has a very high efficiency.
The LM3409 dimming controlled LED driver circuit diagram use Constant Off-Time (COFT) control to regulate an accurate constant current without the need for external control loop compensation.
Using this simple LED flasher circuit can be made a very simple LED flasher which offers the possibility of adjusting the frequency of LED flickering and require a very small amount of current.
Transistors T1 and T2 form a relaxation oscillator whose frequency can be set between 1 Hz and 10 Hz, with potentiometer P1.
Period as the LED stay on is about 5 ms and can thus give a relatively high current value and thus produce intense pulses of light.
Circuit can be used with a supply voltages between 6 V and 15 V.
This LM3909 flashing indicator circuit is made using LM3909 integrated circuit and a seven-segment LED indicator.This LM3909 flashing indicator circuit can be used to display a number (eg number of houses) or to create an optical warning (eg safety belt).
The electronic circuit is very simple and can be powered with a battery "button cell type" (eg AG3 button cell) 1.5 volts.