Which are use to compare with another value of gain. In amplification under few circumstances, the 0 dB gain use as reference. When voltage gain A v is less than one, we can say the gain is negative. When voltage gain A v is greater than one, we can say the gain is positive. The power of amplifier is also express in term of decibel (dB). Generally the voltage gain of amplifier is express in term of decibel. The decibel is defined as logarithmic measurement the ratio of output power to input power. The unit decibel comes from logarithmic response of the human ear to intensity of sound. The formula for cut-off frequency is given below:įor example the cut-off (3dB point) frequency of RC low pass filter is defined as when the resistance is the same magnitude as the capacitive reactance. Since the change is not noticeable, the audio amplifier has a flat response from f1 to f2. This represents the power level of one–half of the power at reference frequency in the mid-range frequency. We can also name these two frequencies as half –Power frequencies because at this range of frequency the voltage gain drops to 70.7 % of the maximum value. The frequency F u is the upper frequency and F L is a lower frequency. upper cut-off frequency and low cut-off frequency. In signal the bandwidth is defined as the range or difference between two frequencies i.e. Here three type of filter are given belowĪs the name suggests itself, a low pass filter pass the low frequency signal whose range from the 0 Hz to a cutoff frequency and attenuate high frequency signal.Ī high pass filter pass the high frequency signal whose range from the above the cutoff frequency and attenuate the low frequency which is below cut-off frequency.Ī band pass filter pass the certain band of frequency which lie in between of high pass and low pass filters. The filter circuits are electronics circuit that allows certain frequency and block remain frequency. As a voltage ratio, this is a fall to approximately 0.707.

Most frequently this proportion is one-half the pass band power, also referred to as the 3 dB point since a fall of 3 dB corresponds approximately to half power. a high pass filter) has fallen to a given proportion of the power in the pass band. In an electronics system the cut-off frequency either below or above which the power output of a circuit, such as a line, amplifier, or electronic filter (e.g. It is also called break frequency or corner frequency. Cutoff frequency is a boundary in a system a system’s frequency response at which energy flowing through the system begins to be attenuated (reflected or reduced) rather than passing through.

Cutoff frequency equation