KrisKasprzak
Well-known member
All,
I have a data logger that measures a batter voltage where the battery will start at 24 VDC but degrade to 21 VDC.
In order to protect from accidental backward connection I have a simple diode to prevent reverse current (which would probably damage my precious Teensy). A voltage divider drops the input volts to a safe measurable amount fed into pin A0. Computing the supply voltage from A0 measurement is pretty easy--and works. Kinda. See attached circuit diagram.
In testing the circuit, I noticed the voltage drop across the diode varies based on voltage. Hence why I'm never able to calibrate the unit across a large range of voltages. I'm using and RL207.
Anyone know of a better way measure 24 VDC with reverse polarity protection?
1. better diode
2. some op amp circuit
3. other?
Thanks in advance.
I have a data logger that measures a batter voltage where the battery will start at 24 VDC but degrade to 21 VDC.
In order to protect from accidental backward connection I have a simple diode to prevent reverse current (which would probably damage my precious Teensy). A voltage divider drops the input volts to a safe measurable amount fed into pin A0. Computing the supply voltage from A0 measurement is pretty easy--and works. Kinda. See attached circuit diagram.
In testing the circuit, I noticed the voltage drop across the diode varies based on voltage. Hence why I'm never able to calibrate the unit across a large range of voltages. I'm using and RL207.
Anyone know of a better way measure 24 VDC with reverse polarity protection?
1. better diode
2. some op amp circuit
3. other?
Thanks in advance.