lcd display, led display,.... ??
for a led display things are fairly obvious
for lcd display, much relies on the polarisation frequency of the display since it's the switching consuming the energy so for a definite answer on lcd..... sorry
LCD - bugger all. The battery if a backlight is not used, then you're looking at a battery life of 3 years or better for most watches.
The backlight uses a LOT of power. A second of backlight may use as much as several hours of normal use.
How much longer would the battery of a digital wristwatch last if one had to press a button to view the time? (Otherwise display is blank.)
I just built a PIC circuit that turns off the LCD when it's not needed. With the LCD on, the current was 2mA. With it off, the current was 0.75mA.
Now, invent a display that only turns on when you are looking at it. Or better yet, only turns on when you are paying attention to it.
--
Regards,
Robert Monsen
"Your Highness, I have no need of this hypothesis."
- Pierre Laplace (1749-1827), to Napoleon,
on why his works on celestial mechanics make no mention of God.
Not much. Watches don't use much power.
quoting:
It would save just a miniscule amount of power, unless we're talking about a LED watch.
A state-of-the-art watch circuit (oscillator and counters, without display) consumes around 80nA. To drive an LCD display you need microamps. Guess the battery's self-discharge is still dominant, so an always-on display does not shorten the battery lifetime.
Early digital watches (e.g., Clive Sinclair's "Black Watch" kit) used a red LED readout. LEDs were/are power hogs so the watch had a button to press for display. At uni I had an evening economics class where the lecturer wore such a watch. After pressing the button and glancing at his watch, there would be an arc of brilliant ruby red traced out amid the gloom of the dingy theatre as he swung his arm back to his side before the display timer shut itself down.
Avoid using the backlighting and alarm if you wish to extend cell life.
-- John Savage (news address invalid; keep news replies in newsgroup)
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