High Pass Filter
A high pass filter is a filter which passes high-frequency signals and blocks low-frequency signals. In other words, high-frequency signals go through much easier and low-frequency signals have a much harder getting through. High pass filters can be constructed using resistors with either capacitors or inductors. A high pass filter composed of a resistor and a capacitor is called a high pass RC filter, while a high pass filter with a resistor and an inductor is called a high pass RL filter.
High pass filters are very common and are used in many type of circuit setups like microphone circuits. Microphones are devices which need the support from both DC and AC signals. Microphones need DC power to turn on and operate. They also can be used to record AC signals, such as human speech, music, noises. The DC is only needed to power the microphone on and should not appear on the output with the AC signal. The DC is for power only and should not be mixed with the audio signal. So to pass the AC signal through and block the DC, we use a high pass filter, so that only the AC signal appears on the output.