Secondary Battery; Using The Tachymeter (When Provided) - Citizen B51 Instruction Manual

11. Secondary Battery

CAUTION:
Handling of Secondary Battery
* Do not attempt to remove the secondary battery from the watch. If the secondary
battery should happen to be removed, store it in a location out of the reach of small
children to prevent it from being swallowed accidentally.
* If the secondary battery has been swallowed, consult a physician immediately and seek
medical assistance.
CAUTION:
Only Use the Specified Battery
* Never attempt to use a battery other than the specified secondary battery in this watch.
Although the watch is constructed to prevent the watch from operating if another type
of battery is installed, if a silver battery or other type of battery is forcibly installed and
the watch is recharged with that battery in use, the battery may become overcharged
causing it to rupture and resulting in the risk of damage to the watch and injury to the
wearer. When replacing, always make sure to only use the specified secondary bat-
tery.
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12. Using the Tachymeter (When Provided)

The tachymeter feature is used to measure traveling speed such as that of an automobile.
In the case of this watch, the average speed can be approximately determined for a certain
distance by measuring how many seconds it takes to travel 1 kilometer (measuring range:
maximum 60 seconds). To determine average speed, start the chronograph simultaneous
to the start of measurement. Stop the chronograph when the vehicle has traveled 1 kilo-
meter. An approximation of the average speed over that distance can be determined by
the position of the chronograph second hand at that time.
60
Chronograph
second hand
Tachymeter
Example:
If it takes 45 seconds to travel
1 kilometer, then the average
speed over that distance is 80
kilometers/hour.
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