Patek Philippe

Swiss Watch Fair 1972 BF 606
An important technical development is this solar powered quartz electronic small clock. No more batteries to replace. Light (200 Lux are enough) is capted by a photoelectric cell. A storage cell with a one-year power reserve takes over during the night or long sunless winters. The resonator is a quartz crystal vibrating at 17t476,27Hertz9 a frequency which is then electronically divided and made to drive the hands by means of a stepping motor. (PATEK PHILIPPE)