Capacitive coupling in analog circuits
– Polyester film capacitors commonly used for coupling between two circuits.
– Coupling capacitor used to connect two circuits, allowing only the AC signal to pass while blocking DC.
– Helps isolate the DC bias settings of the coupled circuits.
– Prevents a 0 volt input from being passed to a transistor, creating continuous amplification.
– Capacitive coupling decreases the low frequency gain of a system.
Capacitive coupling in digital circuits
– AC coupling widely used in digital circuits to transmit DC-balanced signals.
– DC-balanced waveforms are useful in communication systems to avoid voltage imbalance and charge accumulation.
– Most modern line codes designed to produce DC-balanced waveforms.
– Constant-weight codes and paired-disparity codes are common classes of DC-balanced line codes.
Gimmick loop
– Gimmick loop is a simple type of capacitive coupler using closely spaced twisted wires.
– Provides capacitive coupling of a few picofarads between two nodes.
Parasitic capacitive coupling
– Capacitive coupling often unintended, such as between wires or PCB traces.
– Unintended coupling can cause noise and interference.
– Measures taken to reduce coupling, such as separating wires or traces and using ground lines or planes.
– High-frequency or high-gain analog circuits often built over a ground plane to control unwanted coupling.
– Capacitive coupling between amplifier’s output and input can lead to electronic oscillation.
Related concepts
– Coupling (electronics)
– DC block
– Decoupling (electronics)
– Decoupling capacitor
– Direct coupling Source: https://en.wikipedia.org/wiki/Capacitive_coupling
This article includes a list of general references, but it lacks sufficient corresponding inline citations. (August 2023) |
Capacitive coupling is the transfer of energy within an electrical network or between distant networks by means of displacement current between circuit(s) nodes, induced by the electric field. This coupling can have an intentional or accidental effect.
In its simplest implementation, capacitive coupling is achieved by placing a capacitor between two nodes. Where analysis of many points in a circuit is carried out, the capacitance at each point and between points can be described in a matrix form.
