What is Choke Coil – Applications

If someone chokes a person, they can’t breathe, the flow of air is stopped. The name Choke comes from the same idea. There is some energy that we want to Choke or prevent flowing in our circuit in or out of our circuit.

We might want to prevent the power or ground lines in a circuit from interfering with each other like amplifiers where the small signal levels make the first stage sensitive to the small power source variations caused by power stages. Here we can choke off stages simply with resistor-capacitor combinations.

Fig. A choke coil

Similarly, in power line carrier communication, we choke off carrier signal from entering into the power circuit which is done by a Choke Coil popularly known as Wave Trap.

The Choke action is basically an appropriate size of reactance (inductive resistance) for the frequency of what we want to stop flowing, and of course whose reactance doesn’t have an effect on the frequency of proper signals. This takes advantage of the frequency dependence of reactance.

A choke is basically an inductor. It is used when you want to limit an alternating current without increasing the resistance of the circuit, which could lead to heat dissipation. One example of such a use is the choke used in fluorescent lamps.

Applications of choke coil

Choke coils are inductive loads and used for,

  1. Protection of circuits from a steep rise in current which could damage the insulation. Introduction of Choke coil in circuits won’t allow steep increase or decrease in the current rather it will gradually increase or decrease it.
  2. Choke coils used in fluorescent tube generates a transient voltage across the tube to make it conductive as breakdown voltage for gas (mercury vapour and argon, xenon, neon, or krypton) inside the tube is higher than the system voltage.

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