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What is a negative 48Vdc system?

SmartSys Telecom Rectifier

In telecommunication systems it is common to have a supply voltage of -48Vdc. What this means is that the positive terminal is grounded. But why 48V and why ground the positive end? Surely it would be more intuitive to ground the negative end? I’ll answer these questions in turn. Why 48Vdc? This is a trade […]