Power Reserve Indicator
Some high grade watches have an extra dial on the face indicating how much power is left in the mainspring, often graduated in hours the watch has left to run. Since both the arbor and the barrel turn, this mechanism requires a differential gear that measures how far the arbor has been turned, compared to the barrel.
Read more about this topic: Mainspring
Famous quotes containing the words power and/or reserve:
“Thy blood and virtue
Contend for empire in thee, and thy goodness
Share with thy birthright! Love all, trust a few,
Do wrong to none. Be able for thine enemy
Rather in power than use, and keep thy friend
Under thy own life’s key. Be checked for silence
But never taxed for speech.”
—William Shakespeare (1564–1616)
“I do not know what right I have to so much happiness, but rather hold it in reserve till the time of my desert.”
—Henry David Thoreau (1817–1862)