8 ms·
As mentioned in another comment, it’s also close to the safety limit for low voltage systems. IMO solar pioneered (in recent history) 48V DC systems, which is
by matrix2003 2y ago
As mentioned in another comment, it’s also close to the safety limit for low voltage systems.
IMO solar pioneered (in recent history) 48V DC systems, which is an easy multiple of 12V to stay below the 50V “high voltage” safety threshold.
It allowed people to use smaller gauge wire and chain together multiple 12V batteries that are readily available.
- bryanlarsen 2y agoTelephony has been using -48V as a line voltage for a very long time, probably > 100 years.
- matrix2003 2y agoIs that for power deliver, or signaling?
- Kirby64 2y agoBoth. It powers old school telephones.
- p_l 2y ago-48VDC was standard for powering telephone equipment, and is also common standard for direct current datacenter connections. Signaling on POTS easily hit over 100V, btw.
- amanaplanacanal 2y agoI remember getting zapped when the phone rang when I was a teenager back in the 70's. Good times.