I am new to electronics and looking for an ORP probe on Aliexpress for water quality management.
It looks like all of them(for example) don't come with the
module. And I know the probe outputs analog signals.
The pH probes on Ali however all come with a
module. Does it mean ORP probe use a general
module that I have to buy separately?
For Relay, if I would like to control 12V AND 240V devices, will (this) should serve the purpose? I am not sure if 12V and 240V require their own Relay(12V Relay, 240V Relay).