I would like to know why pH electrodes are always with BNC type connectors (or DIN, S7, etc.), but never with "simple" wires.
Can we put a BNC adapter to 2 wires and read the tensions with a multimeter?
Thanks.
Add a comment
|
1 Answer
\$\begingroup\$
\$\endgroup\$
pH probes basically act as batteries, just with very high internal resistance (giga-Ohm range). With such high internal resistance the signal is very "weak", so shielded cable is used to reduce interference. BNC connector also shields the signal, so it is a good choice. Making a measurement circuit is not trivial. For example: you have to take PCB leakage into consideration.
The probe voltage is too low and its internal resistance is too high to be directly read with a multimeter.
