Why are the Outputs of many function generators earth grounded?
As far as I understand grounding the generator or Parts like the chassis can reduce shock hazards if something fails within the generator.
But it also produces ground loops when I try to measure things with my osci.
Ok but why are the BNC Outputs also ground referenced? Cant I simply cut the ground wires from the Outputs to ground so the Chassis is still earth grounded but my outputs are not to get rid of my ground loops? Or does this have any effect I am Not seeing?
update:
Thank you all for your replies. What I did not understand was: the gnd wire is also connected to ne neutral wire in the transformer.
I really did Not get how a current could actually Flow if I only have the signal wire (inner BNC) and only gnd aa the outer shell.
Best Answer
Because you can touch the BNC connector (outer shield), it is often treated in safety testing as part of the case. So, it is possible for a test protocol to make a 30 ampere test current run from that BNC to the AC ground pin on the power cord.
It is easier to justify grounding the shield, or using a CM choke on the signal connector and wiring the BNC shield through that to the case. Or, one can operate a function generator on battery power, with the AC cord and its ground wire completely detached.
To actually float the BNC shield as you want, might only meet safety standards with a class 2 power supply, or battery power.