Here is a little article I wrote for the New Mexico Jeweler’s Association newsletter.
A chronograph is a watch with a traditional time keeping function and with the additional complication of being able to record elapsed time (stopwatch). A chronograph should not be confused with a chronometer, which is a watch which has met a stringent set of standards for precision. Many people wear a chronograph because they like how it looks but anyone who deals with watches on a regular basis should understand how they function.
Chronograph dials come in many different arrangements but the most common analog configuration has hour and minute hands in the center of the watch and a seconds recording hand in the center that only moves when the chronograph is activated. At other times it should rest at 12 o’clock. The time seconds hand is usually located in a sub-dial and runs all the time. There are usually additional sub-dials for recording elapsed minutes and hours or tenths of a second. The tenths of second recorder stays still even when the chronograph is running but moves to indicate the tenth of a second when the chronograph is stopped and returns to zero when the chronograph is reset.
Chronograph buttons are almost always arranged the same way. The top button (at 2 o’clock) starts and stops the chronograph function. The bottom button (4 o’clock) temporarily stops the chronograph for reading a lap time (quartz watches only) if pressed when the watch is running, or resets all the hands to their zero positions if pressed when the chronograph is stopped.
Many chronographs today have a tachymeter scale around the perimeter of the watch. This scale is used to determine ones speed. To use the tachymeter, the chronograph is activated as you travel past a specific point and stopped after you have traveled one mile. Your speed is indicated by reading the number on the scale indicated by the seconds recording hand.
Continuous operation of a quartz chronograph causes the battery to deplete much faster, but does not cause any damage to the watch. Many people believe that continuous operation of a mechanical chronograph causes additional wear and tear. These watches, however, are designed to be operated and continuous operation will not cause them to need service any sooner than if they are only used occasionally.