Watch black elite
Clock based on the count of the periods of the oscillations from the oscillator with the help of the electronic circuit and the output on the digital display.
First electronic wristwatch had a led display, but they could show time is very short: too gluttonous were LEDs. Then used the properties of liquid crystals to be oriented in an external electric field and to pass light with one polarization direction. Being placed between the two polarizers, the light from an external source is absorbed by the system, the polarizer of the liquid crystal polarizer-reflector in the presence of an electric field was dark and form a picture element. The result was significantly reduced power consumption, and battery replacement is much less.