LM3914 with LED bargraph display? or do you want fewer LEDs? Voltage Reference driving three or four LM339 comparators, but that is more complicated than the LM3914 would be.
When the battery:
- A maximum load (12V) I wanted the green light;
- 1V unload when it came down to the 11v yellow LED light;
- When the battery was 10V for the red LED would light up!
this is what I need, serves to indicate the level of the battery of my car
Gentlemen thanks for your PC board layout, it is much more professional than mine. I built a number to these devices and enclosed them in a small plastic box. Original design used a bridge rectifier as the input and as a result it was not polarity sensitive.
I usually etch my own boards. I print the layout on a transparency and use positive sensitized boards. Anyway here is the single sided layout. The two large circle's with an inner circle were for placing the circuit board on the mounting supports in the enclosure. The enclosure used was a PACTEC model JM12-IE