Thanks, that is almost exactly what I have done on the breadboard circuit. Instead of trying to use pins 7 and 8 of the LM3918 to provide a Low and High reference, I use a resistor divider fed from the stabilised voltage supply. I too have shorted the high order LED pins so that the last green LED (the fourth) will stay lit (you have used an extra LED).
Using the 7815 is less parts than using the op-amp maybe I should have thought of that and it was mentioned I think in this thread ? It uses 4-5mA at least compared to 2-2.5mA for the op-amp version. We can also replace the op-amp with a single pass transistor, a bit less accuracy but we'd be down to 1.5mA.
On the breadboard version I am trying to get it to be accurate enough, will take a picture in a sec.
Using the 7815 is less parts than using the op-amp maybe I should have thought of that and it was mentioned I think in this thread ? It uses 4-5mA at least compared to 2-2.5mA for the op-amp version. We can also replace the op-amp with a single pass transistor, a bit less accuracy but we'd be down to 1.5mA.
On the breadboard version I am trying to get it to be accurate enough, will take a picture in a sec.