Chuck Kimball wrote:
>
>
> Yes, trying to monitor the local -48 Power system, and solar charging
> system with my APRS digi +12VDC that accepts 0-5VDC input.
>
> Chuck
Probably the simplest would be to use an opamp as a X 0.1 inverting
amplifier:
10K
--/\/\/\/\--
| |
100K | |\ |
-48v ---/\/\/\/\-----|-\ |
| |------ to controller 0 to 5v input
gnd--|+/
|/
The scale factor will be -10:1 on your controller (ie a reading of 4.4V
would mean -44 volts at the battery).
If there is any possibility of losing opamp power while connected to the
-48 volts, you should also place a Schottky diode from the opamp -input
to ground (cathode to opamp and anode to ground).
Ed Yoho
W6YJ
