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--- vibrations_per_hour [03.07.2022 15:39] – created - external edit 127.0.0.1
+++ vibrations_per_hour [02.05.2023 19:14] (current) – [Overview] gerdlothar
@@ Line 1: / Line 1: @@
+====== Vibrations per hour ======
+The [[balance]] of a watch oscillates at a predictable rate, typically referenced as **vibrations** or **alterations per hour** (**A/h**) or **hertz** (**Hz**).
+===== Overview =====
+One vibration ("semi-cycle" or "beat") is a movement limited by two end positions. So the [[balance wheel]] of a watch may makes eight semi-cycles per second, which is 28,000 per hour. This is often divided by two and counted in hertz (Hz). Thus, a 28,800 A/h movement moves at 8 semi-cycles per second or 4 Hz.
+The number (frequency) of the vibrations of the [[balance wheel]] is determined by the diameter and the weight of the balance wheel and [[hair spring]]. The higher the frequency, the greater the reduction to the [[gear train]] must be.
+Typical watch oscillation rates:
+^A/h ^  Hz^  V/s^Notes ^
+|18,000 |  2.5|  5|Typical pocket watch|
+|19,200 |  2.6|  5.2|Faster pocket watch|
+|21,600 |  3|  6|Classic watch|
+|28,800 |  4|  8|Classic "high-beat"|
+|36,000 |  5|  10|Modern "high-beat"|
+|72,000 |  10|  20| |
+===== See Also =====
+  * [[High-beat]]
+  * [[Rate]]
+{{tag>Terms}}