What is Galvanic isolation

 Galvanic isolation is a principle in electrical engineering that involves separating electrical circuits to prevent the flow of direct current (DC) and unwanted alternating current (AC) between them, while still allowing the transfer of signals and power. Essentially, there is no direct conductive path between the isolated circuits; instead, energy or information is transferred via a field (magnetic, electric, or light).

  

Here's a breakdown of the concept and its function:

Function:

Prevents DC and Unwanted AC Current Flow: The primary function is to block any direct electrical connection between circuits. This is crucial when there are significant differences in ground potential or when high voltages are present in one part of the system that could be dangerous to other parts.   

Allows Signal and Power Transfer: Despite the electrical separation, galvanic isolation allows the necessary signals and power to be transmitted between the isolated circuits. This is achieved through various coupling mechanisms: 

Magnetic Coupling (Transformers, Inductors): Energy is transferred via a changing magnetic field. This is common in power supplies and for isolating data signals.   

Optical Coupling (Optocouplers): Signals are transmitted using light. An LED on one side emits light, which is detected by a photodetector on the other side.   

Capacitive Coupling (Capacitors): Alternating current signals can pass through capacitors, allowing for signal transfer while blocking DC.   

Hall Effect Sensors: Magnetic fields generated by current flow are sensed and converted into a proportional electrical signal, allowing for non-contact current sensing and isolation.   

Breaks Ground Loops: When multiple circuits share a common ground but have different ground potentials, unwanted currents (ground loops) can flow, leading to noise and interference. Galvanic isolation breaks these loops by eliminating the direct electrical connection.   

Provides Safety: It protects users and equipment from dangerous voltage levels and fault conditions by preventing current from flowing from high-voltage parts of a system to low-voltage parts or to ground through a person.   

Improves Noise Immunity: By preventing the transfer of common-mode noise (noise present on both lines of a circuit), galvanic isolation enhances the reliability and accuracy of signal transmission, especially in noisy electrical environments like industrial settings.   

Matches Impedance (in some applications): While not its primary function, transformers used for galvanic isolation can also be designed to match impedances between circuits for optimal power transfer.   

In essence, galvanic isolation acts as an invisible barrier that ensures safety, prevents unwanted current flow and noise, and allows different parts of an electrical system to interact effectively without direct electrical connection. This is particularly important in applications like medical equipment, industrial controls, communication systems, and power supplies, including those used in Manakunnam and across Kerala.