G04C10/00—Arrangements of electric power supplies in time pieces
G04C10/02—Arrangements of electric power supplies in time pieces the power supply being a radioactive or photovoltaic source
G—PHYSICS
G04—HOROLOGY
G04G—ELECTRONIC TIME-PIECES
G04G9/00—Visual time or date indication means
G04G9/0017—Visual time or date indication means in which the light emitting display elements may be activated at will or are controlled in accordance with the ambient light
H—ELECTRICITY
H03—ELECTRONIC CIRCUITRY
H03K—PULSE TECHNIQUE
H03K21/00—Details of pulse counters or frequency dividers