Frequency is the number of occurrences of a repeating event per unit time. It is also referred to as temporal frequency. The period is the duration of one cycle in a repeating event, so the period is the reciprocal of the frequency.
Definitions and units
For cyclical processes, such as rotation, oscillations, or waves, frequency is defined as a number of cycles, or periods, per unit time. In physics and engineering disciplines, such as optics, acoustics, and radio, frequency is usually denoted by a Latin letter f or by a Greek letter ν (nu).
In SI units, the unit of frequency is hertz (Hz), named after the German physicist Heinrich Hertz. For example, 1 Hz means that an event repeats once per second.
A traditional unit of measure used with rotating mechanical devices is the revolutions per minute, abbreviated rpm. 60 rpm equals one hertz.
The period is usually denoted as T, and is the reciprocal of the frequency f:
The SI unit for period is the second.
- Giancoli, D.C. (1988), Physics for Scientists and Engineers (2nd ed.), Prentice Hall, ISBN 013669201X
- Davies, A. (1997). Handbook of Condition Monitoring: Techniques and Methodology. New York: Springer. pp. 275. ISBN 9780412613203. https://books.google.com/books?id=j2mN2aIs2YIC&pg=RA1-PA275.
- Bakshi, K.A.; A.V. Bakshi, U.A. Bakshi (2008). Electronic Measurement Systems. US: Technical Publications. pp. 4-14. ISBN 9788184312065. https://books.google.com/books?id=jvnI3Dar3b4C&pg=PT183.
- Elert, Glenn; Timothy Condon (2003). "Frequency Range of Dog Hearing" (in English). The Physics Factbook. https://hypertextbook.com/facts/2003/TimCondon.shtml. Retrieved 2008-10-22.
- National Research Council of Canada: Femtosecond comb; The measurement of optical frequencies
- Conversion: frequency to wavelength and back
- Conversion: period, cycle duration, periodic time to frequency
- Keyboard frequencies = naming of notes - The English and American system versus the German system
- Teaching resource for 14-16yrs on sound including frequency
- A simple tutorial on how to build a frequency meter