One thing that comes to mind is that the TV power connector might not have an earthing pin to protect it from lightning striking the antenna. Since the whole TV electronics is floating, lightning voltages (which are relative to earth) might prove to be less damaging.
First some definitions and concepts. Then some simple experiments.
Your are confusing earth ground with something called safety ground. Your TV has no safety ground connection because a third ground inside the TV is isolated - a floating ground. A voltage difference between a floating ground and safety ground is undefined. It may or may not harm you if you touch both simultaneously.
In the meantime, anything conductive outside of that TV must be galvanically isolated from floating ground. Isolated does not mean no electrical conductivity. Isolated means minimal electrical connection.
Two tests for sufficient human safety. First, plug the TV into a working (and pre-tested) GFCI outlet. Connect a jumper cable from that audio ground to the safety ground (ie a screw holding the wall receptacle cover plate). This test should not trip the GFCI. Some current will pass from that audio ground into wall receptacle. Current must be so low as to not trip GFCI.
Second, measure that leakage current using the meter set for AC current. Measure well less than 150 microamps (0.15 milliamps) from audio ground to wall receptacle 'safety ground'. Some leakage current should be measured. Current so low as to not threaten human life and not trip the GFCI. Galvanic isolation does not mean zero current. It means minimal leakage current.
BTW, the safety ground > I just bought a new TV and found
Right, thats understood. Now since the TV has 2000W exceptionally good audio amplifier, I would like to connect audio out from my PC to audio in of TV.
As I understand, your mentioned example current (0.15 mA) would flow from the TV signal ground to the Sound Card GND tracks, then to the mother board GND tracks, then to the POWER SUPPLY gnd wire, then to the WALL OUTLET safety GND.. (PC has earth pin)
Although this current is too small, I presume it is not worth taking a risk. Moreover, if some static phenomenon occurs in the TV, it might damage the PC!
If wire is grounded via computer and soundcard (a common mode connection), then no static problem exists. None.
Static is not created by the TV. Voltage leakage from a floating ground, as described earlier, may be created by the TV. That leakage must be so low as to not harm humans, which means that leakage is too low to harm electronics. If worried, then make the connections before powering computer and TV. A redundant layer of protection.
Earlier noted was that a defective TV (galvanic isolation failed) might conduct current through you when you touch both audio ground and safety ground simultaneously. But then this is what those two experiments do. They confirm the defect does not exist.
I d> Right, thats understood. Now since the TV has 2000W exceptionally good
Peter, why not do a self analysis before posting sarcastic comments for a nation of 1 billion ? I wouldn't be surprised if someone from India made you feel not very comfortable for what you just wrote.
Here's what I did: Connected TV Signal earth to safety earth directly by a thick cable (16 SWG x 10) and then connected the PC to the TV. The tester stopped showing any presence of voltage on the TV signal earth, and the reception is ok. PC is ok.
"Peak Music Power" is a term you need to become familiar with. And while a
29" TV is swell, it's hardly out-of-this-world. Anyway, glad you like it. And in answer to the original question, yes you can connect your PC audio output to the TV safely (assuming the PC is safe to start with). If it really concerns you that there may be a problem you could hunt out some audio isolation transformers to put between the PC and the TV, but unless you paid a reasonable amount of money it would degrade your audio response.
Temporarily disconnect computer and ground cable. Measure AC current from audio ground to that new safety ground wire. Current should be on the order of less than 1 milliamp. Unlike the experiment with safety ground wire, this test actually reports something useful.
Of course that grounding cable will eliminate voltage. Wire eliminating voltage tells us nothing useful. But is that voltage created by a leakage that is too large or by a leakage that is acceptable? You still have not answered a question that determines whether a threat to computer, et al exists.
If your meter does not have an AC amperage option, then connect audio ground to safety ground via a 10K ohm resistor. If the leakage is 150 microamps, then AC voltage across that resistor will be 1.5 volts. If the voltage is less, then the leakage (and need for safety ground wire) is irrelevant. If voltage across resistors is more, than your TV may be a threat to computer and human life.
If leakage is less than 150 uamps, then even a wire about the size of a human hair would have been sufficient to ground out the leakage.
Aga> Here's what I did: Connected TV Signal earth to safety earth directly
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