Hello, first time poster, so please be gentle.
I want to build a circuit to display the value of a signal on a LED bar graph. I've gotten my breadboard prototype working, but not perfect. The more and more I research, the more and more confused I become.
The circuit closely follows this design:
**broken link removed**
Except its in DOT mode, the optional capacitor isn't present, and I have a voltage regulator dropping the source voltage from 12v to 5v, as to keep the chip from working overtime dissipating heat.
The voltage range I would like for it to operate within is 0.08v to 3.87v. The LED bar graph I'm using is a **broken link removed**, and used a current of 0.030A in my calculations. My initial design is using the following resistors: R1 = 360Ω, R2 = 755Ω
It works, but my ranges aren't perfect I could have my resistors off a little since I ordered the wrong ones initially, so I had to combine some to get close to what I wanted.
So after some more research, I stumbled upon the calculator hosted here. Playing with it at home, it was yelling at me about the LED current. So I tried using a lower current of 0.020A, with a R1 = 570Ω and R2 = 1190Ω, and its still blinking at me.
So, this is making me wonder:
Do I need to lower the Vled from 5V to something like 2V?
Am I using the wrong value for iLED?
What exactly are those colored boxes in the calculator and how do they differ from the sliders?
How do I alter RLo to allow my range to operate from 0.08 to 3.87? (I figured 0 was close enough, but now I'm not sure)
Thanks!
I want to build a circuit to display the value of a signal on a LED bar graph. I've gotten my breadboard prototype working, but not perfect. The more and more I research, the more and more confused I become.
The circuit closely follows this design:
**broken link removed**
Except its in DOT mode, the optional capacitor isn't present, and I have a voltage regulator dropping the source voltage from 12v to 5v, as to keep the chip from working overtime dissipating heat.
The voltage range I would like for it to operate within is 0.08v to 3.87v. The LED bar graph I'm using is a **broken link removed**, and used a current of 0.030A in my calculations. My initial design is using the following resistors: R1 = 360Ω, R2 = 755Ω
It works, but my ranges aren't perfect I could have my resistors off a little since I ordered the wrong ones initially, so I had to combine some to get close to what I wanted.
So after some more research, I stumbled upon the calculator hosted here. Playing with it at home, it was yelling at me about the LED current. So I tried using a lower current of 0.020A, with a R1 = 570Ω and R2 = 1190Ω, and its still blinking at me.
So, this is making me wonder:
Do I need to lower the Vled from 5V to something like 2V?
Am I using the wrong value for iLED?
What exactly are those colored boxes in the calculator and how do they differ from the sliders?
How do I alter RLo to allow my range to operate from 0.08 to 3.87? (I figured 0 was close enough, but now I'm not sure)
Thanks!
