| ??? 11/27/07 12:41 Read: times Msg Score: +1 +1 Good Answer/Helpful |
#147448 - Dwhatever9 shell connection to GND... Responding to: ???'s previous message |
... is important in case you are going to connect two devices which are not sharing a ground level reliably.
When you mate the connectors, the shells touch first, so any differences in ground level are going to be equalized prior the signal pins touch. Otherwise, there is no guarantee which pin will touch first, and if it is a signal pin, it carries all the voltage difference between the grounds (plusminus the actual voltage level of that particular output). Just try to measure the voltage difference of "grounds" of several pieces of your equipment. You might be perhaps surprised. It's even better to use an oscilloscope, as much of that difference is AC (50/60 Hz hum and other induced voltages). JW |
