| Cycle per second | |
|---|---|
 A 1 MHz military-gradecrystal resonator with anoctal base, marked "1000 KC" for 1000 kilocycles per second. | |
| General information | |
| Unit of | Frequency, rotational frequency |
| Symbol | cps, c/s |
| Conversions | |
| 1 cpsin ... | ... is equal to ... |
| SI units | 1 Hz = 1 s−1 |
Thecycle per second is a once-common English name for the unit offrequency now known as thehertz (Hz). Cycles per second may be denoted byc.p.s.,c/s, or, ambiguously, just "cycles" (Cyc., Cy., C, or c). The term comes from repetitive phenomena such assound waves having a frequency measurable as a number of oscillations, or cycles, per second.[1]
With the organization of theInternational System of Units in 1960, the cycle per second was officially replaced by thehertz, orreciprocal second, "s−1" or "1/s". Symbolically, "cycle per second" units are "cycle/second", while hertz is "Hz" or "s−1".[2] For higher frequencies,kilocycles (kc), as an abbreviation ofkilocycles per second were often used on components or devices. Other higher units likemegacycle (Mc) and less commonlykilomegacycle (kMc) were used before 1960[3]and in some later documents.[4] These have modern equivalents such as kilohertz (kHz), megahertz (MHz), and gigahertz (GHz). Following the introduction of the SI standard, use of these terms began to fall off in favor of the new unit, with hertz becoming the dominant convention in both academic and colloquial speech by the 1970s.[5]
Cycle can also be a unit for measuring usage ofreciprocating machines, especiallypresses, in which casescycle refers to one complete revolution of the mechanism being measured (i.e. the shaft of areciprocating engine).
Derived units includecycles per day (cpd) andcycles per year (cpy).
The 7000- and 14,000-kc. grid coils are wound with No. 18 enameled wire ...
The Monode described here is usable at frequencies below 144 Mc. with slight modification.