Its construction is very simple. Just a dielectric is present in between the parallel plate capacitors. This coupling capacitor is good at obtaining final output as AC signals. There exist decoupling capacitors as well in which the output generated is consisting of DC signals. Hence coupling capacitors are preferred in analog circuits.
AC coupling capacitors are frequently used in multi-gigabit data links. Many current data standards require AC coupling (for example PCIe Gen 3, 10 Gb Ethernet, and so on). In addition, there exist incompatible common mode voltages between drivers and receivers, for which AC coupling is the simplest means to solve this problem.
Ceramic surface mount capacitors are frequently used for AC coupling in multi-Gbps applications where they are required by a standard or needed to connect two devices with incompatible I/O common mode voltages. The tendency is to use the highest quality coupling capacitors available.
Some of them are listed below. In the purpose of the communication of the power line, the coupling capacitors are preferred. After the trap of wave, these are placed. It ranges from 2200 pf to 10,000 pf. If the circuit possesses high-frequency signals then the capacitor functions in such a way that it offers low impedance value and vice-versa.
During multiple stages, a capacitor is connected between the two stages. So that output of one stage can be coupled as the input to the next stage. In this coupling capacitors are utilized in the BJT’s. From the above description it can be known that the coupling capacitor is mostly part and parcel of any circuit and.
On the other hand, to preserve low frequency data content, required coupling capacitance is in the range of 0.1 mF to 4.7 mF, with self-resonances in the 100s of MHz. In some cases, the approach is to use the “best” capacitors available (for example, low ESR), intended for power supply decoupling, and hope that it is good enough.