Common Mode Choke

Here's how the common choke works:

1. Structure: A common choke typically consists of two or more windings wrapped around a magnetic core. The core can be made of ferrite or other magnetic materials that enhance its inductive properties.

2. Common Mode Current: When current flows through the wires connected to the choke, both the positive and negative currents create magnetic fields in the same direction. This is known as common mode current.

3. Induction: The magnetic field generated by the common mode current induces an opposing voltage in the choke. This helps to resist the flow of high-frequency noise and EMI while allowing the desired signals or lower-frequency currents to pass through.

4. Differential Mode Signals: Unlike common mode currents, differential mode currents (which flow in opposite directions in the windings) do not generate significant opposing voltage, allowing these signals to pass through the choke with minimal attenuation.

5. Applications: Common mode chokes are commonly used in power supply circuits, data lines, and communication systems to filter out noise and improve signal integrity.

In summary, a common choke effectively filters out unwanted high-frequency noise while allowing the desired signals to pass, making it essential for maintaining the performance of electronic systems.