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  1. #1
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    Difference between ground symbols

    Hi,

    Why there is different types of symbols?
    Are they isolated from each others in PCB?

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    Thanks

    •   Alt18th May 2018, 07:57

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  2. #2
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    Re: Difference between ground symbols

    First one is Chassis Ground (Connected to the chassis of the circuit).

    Second one is Earth Ground used for zero potential reference, for electrical shock protection. Earth-ground symbol represents a real connection to earth.

    Third one is Signal Grounds. Signal Ground is a reference point from which that signal is measured, same circuit may have different signal ground due to different potentials or analog ground /Digital ground

    Chassis ground should connect to earth ground but signal grounds should not interconnect and not connect to chassis or earth.

    Signal grounds are always isolated (different potentials or analog ground /Digital ground) and also isolated with earth or chassis ground


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    •   Alt18th May 2018, 08:51

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  3. #3
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    Re: Difference between ground symbols

    Hi,

    ... because they have different meanings.

    a battery operated system usually has a signal_GND. This is where each signal refers to. But it may also have a shielding, this is chassis_GND. Chassis_GND may be connected with signal_GND, but not at a random point.. it will be connected to signal:GND in a way that Chassis_GND currents have low impact on signal_GND and itīs reference to the signals.

    A mains operated device with metal case will have Earth_GND. Itīs for your life protection. It may be directely connected to signal_GND, but is may be connected with any device in sereis, like a capacitor or a resistor.

    One is more for safety, one is for operation, one is for noise suppression....

    Klaus
    Please donīt contact me via PM, because there is no time to respond to them. Thank you.


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