What is the frequency?
So, before you determine what is measuredfrequency, it is important to understand what it is? We will not delve into complex physical terms, but we still need some concepts from this discipline. First, the concept of "frequency" - can only refer to any periodic process. That is, it is an action that is constantly repeated in time. The rotation of the Earth around the Sun, the contraction of the heart, the change of day and night - all this occurs with a certain frequency. Secondly, its frequency, or periodicity of oscillations have phenomena, or objects that we, people, can seem quite static and immobile. A good example of this is ordinary daylight. We do not notice any of its changes, or flicker, but it, nevertheless, has its own frequency of oscillations, since it represents high-frequency electromagnetic waves.
Units
What is the frequency, in what units? For low-frequency processes, there are individual units. For example, on a cosmic scale, the galactic year (the revolution of the Sun around the center of the Galaxy), the Earth year, the day, etc. It is clear that to measure smaller quantities, it is inconvenient to use such units, therefore in physics the more universal value "second to minus first degree" (with-1). Perhaps you have never heard of such a measure, and it is not surprising - it is usually used only in scientific, or technical literature.
Fortunately for us, in 1960, the measure of frequencyhesitation was named for the honor of the German physicist Heinrich Hertz. This value (hertz, short Hz) and is used by us today. It denotes the number of vibrations (impulses, actions) performed by the object in 1 second. In fact, 1 Hz = 1 s-1. The human heart, for example, has a frequencyoscillations of approximately 1 Hz, i.e. is reduced once per second. The frequency of the processor of your computer, maybe, say, 1 GHz (1 billion Hertz) - this means that it takes 1 billion actions per second.
How to measure the frequency?
If we talk about measuring the frequencies of electricalthe first device with which each of us is familiar is our own eyes. Due to the fact that our eyes are able to measure the frequency, we distinguish colors (recall that light is electromagnetic waves) - the lowest frequencies we see as red, high-frequency - it's closer to purple. To measure lower (or higher frequencies), people invented a variety of instruments.
In general, the main ways to measure frequency aretwo: direct counting of pulses per second, and a comparative method. The first method is implemented in frequency meters (digital and analog). The second is in the frequency comparators. The measurement method with the frequency meter is simpler, while the comparator measurement is more accurate. One of the varieties of the comparative method is the measurement of frequency with the help of an oscilloscope (we are familiar from the physics classrooms since school) and so-called. "Lissajous figures". The disadvantage of the comparative method is that two oscillation sources need to be measured, and one of them must have a frequency already known to us. Hopefully our little research was interesting to you!
