The complicated watch may  have a feature that can  measure the speed, do you know ?And do you know how to use the watch TACHYMETER to measure the speed?

What is the Watch TACHYMETER?

       Watch speed measurement is a chronograph with a decreasing number of 500/400/350 in the outer ring of the watch. These represent the physical quantity as speed in kilometers/hour.

This bezel is called TACHYMETER,Megalith watch for example:

How to use the TACHYMETER of watch to measure the speed? 

8091M | Quartz Men Watch | Stainless Steel Band

How to use the watch speed measurement:

      The method of use is taken as an example of a vehicle traveling on a highway, because the distance indicator is generally vertical on the highway; when the stop point is started, the stopwatch is started, the stopwatch is timed from 12 o'clock, and when moving 1 km, the timing is stopped, at this moment The number pointed to by the second needle is the average speed of the previous mile.

       For example, there is 60 at 12 o'clock, because one minute walks 1 km, then the speed is 60 km / h.


How do the Watch TACHYMETER work?

       How is the position corresponding to the number on the bezel calculated? if you kow this then it's actually really easy for you to know how the TACHYMETER can work.

Want to know that the number 500 should be engraved in that position? Then you need to do a simple division; that is, how long it takes for the calculus to travel 1 km at a speed of 500 km/h, in seconds.

       1 hour = 3600 seconds, then 500 kilometers needs 3600 seconds to complete. According to the principle of proportionality, the time required for 1 kilometer is 3600/500 = 7.2 seconds, so 500 must be engraved on the dial at 7.2 seconds. For the same reason, 400 should be engraved in 3600/400 = 9 seconds, while 100 is engraved in 36 seconds.


 Does TACHYMETER work not matter what speed?

At speeds below 60 km/h, the tachometer cannot be used directly unless a low speed scale is added.The maximum and minimum values on the bezel are the speed ranges that can be tested.