Hi i have searched the web and i have found a few circuits that helped me along the way but im stuck.. please help.
I have the basic LM3916 datasheet (schematic) working with the 10 leds, so thats fine.
But when I swap the led on say pin 1 to 10 on the led side with a TIP121, I connect the fly lead from pin one to the base of the transistor, connect a new power supply (I'm using 4 leds (in series) that use a voltage of 8v in total so my power supply is 8v so that's fine.
I connect this power supply to the leds in series on the + side.
They feed into the left leg of the TIP121 on the right leg i connect the - feed from the battery.
When i do this i think this second power supply is sending power back down towards the lm3916 chip. How I know this is I left one of the led's still in place, and when I connected the tip121 to the lm3916, both the new 4 leds with the tip121 and the original led at the Lm3916 stay on?
Can any one give me any help please?
I have the basic LM3916 datasheet (schematic) working with the 10 leds, so thats fine.
But when I swap the led on say pin 1 to 10 on the led side with a TIP121, I connect the fly lead from pin one to the base of the transistor, connect a new power supply (I'm using 4 leds (in series) that use a voltage of 8v in total so my power supply is 8v so that's fine.
I connect this power supply to the leds in series on the + side.
They feed into the left leg of the TIP121 on the right leg i connect the - feed from the battery.
When i do this i think this second power supply is sending power back down towards the lm3916 chip. How I know this is I left one of the led's still in place, and when I connected the tip121 to the lm3916, both the new 4 leds with the tip121 and the original led at the Lm3916 stay on?
Can any one give me any help please?
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