I've spent the entire afternoon fruitlessly trying to figure out how to do what I want to do, even though I know it's very common. Now I need someone who actually knows what they are doing to point me in the right direction.
I have an analog voltmeter installed in a (vintage) device, that I have discovered by trial and error produces full deflection with 3V. I have a two cell LiFeP04 battery in it, and I would like to connect it to the voltmeter so it shows zero when the battery reaches about 5.6V (2.8V per cell) and full deflection when the battery is about 7.3V (2.65V per cell).
I've found a post that shows how to do it for a car battery using a zener diode, a resistor and a pot. Looks ideal. I have been trying to figure out what values I need for the pot and the resistor using this circuit simulator but I have no idea what the values for the zener diode mean in the simulator. In the circuit description it says that the zener voltage controls the low voltage, so I presumably I need a zener as close as I can get to 5.6V, but I don't know how to specify that in the simulator. Trying random combinations has got me nowhere.
Can anybody please advise me what values I need for the resistor and the pot?
All assistance gratefully received.
:-(
I have an analog voltmeter installed in a (vintage) device, that I have discovered by trial and error produces full deflection with 3V. I have a two cell LiFeP04 battery in it, and I would like to connect it to the voltmeter so it shows zero when the battery reaches about 5.6V (2.8V per cell) and full deflection when the battery is about 7.3V (2.65V per cell).
I've found a post that shows how to do it for a car battery using a zener diode, a resistor and a pot. Looks ideal. I have been trying to figure out what values I need for the pot and the resistor using this circuit simulator but I have no idea what the values for the zener diode mean in the simulator. In the circuit description it says that the zener voltage controls the low voltage, so I presumably I need a zener as close as I can get to 5.6V, but I don't know how to specify that in the simulator. Trying random combinations has got me nowhere.
Can anybody please advise me what values I need for the resistor and the pot?
All assistance gratefully received.
:-(