Hi,
The best way to describe my project is like a battery charge level status indicator. I'm using a 555 IC to a 4029 binary up/down counter to a 4028 binary decoder. There are ten LEDs connected to the ten 4028 outputs. The bit I'm struggling with is getting multiple LEDs to light simultaneously, eg. for output value 5 I want 5 LEDs to light up then for output value 6, 6 LEDs etc. I've attached a picture of two solutions I've found that work - one with LEDs in parallel, one with them in series. I prefer the parallel circuit I don't need to determine a resistor value for each combination of LEDs - also no risk of "running out" of voltage. I am powering from a 9V DC battery.
My question is whether I'm making this overly complicated? It seems I need a lot of diodes considering the LEDs are diodes themselves. Also I'm not sure if I will reach a limit as to how much current the ICs will pass through them (eg if I keep adding more LEDs) or whether that's just limited by the size of battery I use. I could use transistors to make sure I give the LEDs full power but that would be even more complicated and not sure it's required.
Thanks a lot for any help in clearing this up for me
Andrew
The best way to describe my project is like a battery charge level status indicator. I'm using a 555 IC to a 4029 binary up/down counter to a 4028 binary decoder. There are ten LEDs connected to the ten 4028 outputs. The bit I'm struggling with is getting multiple LEDs to light simultaneously, eg. for output value 5 I want 5 LEDs to light up then for output value 6, 6 LEDs etc. I've attached a picture of two solutions I've found that work - one with LEDs in parallel, one with them in series. I prefer the parallel circuit I don't need to determine a resistor value for each combination of LEDs - also no risk of "running out" of voltage. I am powering from a 9V DC battery.
My question is whether I'm making this overly complicated? It seems I need a lot of diodes considering the LEDs are diodes themselves. Also I'm not sure if I will reach a limit as to how much current the ICs will pass through them (eg if I keep adding more LEDs) or whether that's just limited by the size of battery I use. I could use transistors to make sure I give the LEDs full power but that would be even more complicated and not sure it's required.
Thanks a lot for any help in clearing this up for me
Andrew