ttj - Tom Jones

  Powering (or charging) a thinkpad used to involve a thick three-core mains cable with plug, a large transformer unit, and a DC lead integrated with the DC jack for the laptop end.  The full assembly above comes in just short of 500g.  It's always been 20V. It was possible to save some travel weight by making your own very short mains leads, splicing the DC lead, buying an alternative transformer, and so on, but not by much.  I even saved some weight by importing A Merkin lenovo transformers, which are perhaps class II appliances, but in any case had a two-connector figure-8 (C8) connector, only requiring a thinner 2-core mains lead.  But the transformer was always big. On their way to USB-C PD, thinkpads had a variety of other DC inputs: the square one, the thin round one.  Even when thinkpads, for example the X1 Carbons, started to have USB-C PD inputs more than 5 years ago, lenovo shipped them with bulky, heavy power supplies, with the transformer still...