It is simple voltmeter is marine waterproof gaute. Chrome and brass waterproof cylinder, non-removable piece
from front is hand and scale 8-16V
from behind is + and - terminals
it should show the magnitude of the voltage applied to the terminals.
unfortunately it is somehow damaged or something is missing and 12V shows it if it is on the terminals is 2,83V. if aplied 12V is
voltmeter overloaded and hand stuck to the right.
has a presumption, something is destroyed in the meter, by overvoltage or polority reversal, etc.
In any case, in order for it to point at least approximately correctly, I must insert something between the voltmeter terminals and the voltage wires that will cause it to point correctly.
I try ,
- zener diode and subtract its voltage
- resistance in series with the internal resistance of the voltmeter
- resistor divider and apply a divided voltage to the voltmeter
everything works, but everything has a different linearity than a voltmeter, and in some part of the measurement it inserts a large (visible) error
Yes, it is more of an orientation measurement, in fact more of a decorative matter, but I would still like it to show it as best as possible.