Effect of AC and DC on Electrical Choke coil: Electronic Ballast Circuit Diagram and Working. Chokes are fixed inductors primarily intended to "choke" off alternating currents, including rf from DC supply lines. Typical of the economical chokes which tend to look like resistors and are color coded in a similar fashion in the following figure 2 which is a choke color code chart.

It is used in resonance circuits. Inductors designed for use as chokes are usually distinguished by not having the low-loss construction (high Q factor) required in inductors used in tuned circuits and filtering applications. The common-mode (CM) choke, where two coils are wound on a single core, is useful for suppression of electromagnetic interference (EMI) and Applications of Electrical Choke coils: 1. A choke, as with any inductor, also exhibits some degree of self-capacitance or "distributed capacitance".

‘f’  is the frequency and ‘L’ is the inductance. Chokes are divided into two broad classes: Audio frequency chokes (AFC) usually have ferromagnetic cores to increase their inductance.

A signal generator, serving as a voltage source, is connected to an amplifier. A choke coil is used as an inductor in an electrical circuit. It is often referred to as the choke effect because this condition is the restriction of a grounding electrode conductor from performing its function. Friday, 29-Jun-2018 02:34:41 PDT. A capacitor does not work so. This capacitance in conjunction with the design inductance are resonant at some particular frequency. URL - https://www.electronics-tutorials.com/basics/chokes.htm. Most of them wondered what is wrong with the oldest type of choke.

Looking for more? Copyright © 2000, all rights reserved.

However, the DM current flowing through the windings will generate high emitted near magnetic field since the windings are negative coupled in this case.

Increasing the operating frequency further again we find the choke's reactance is dominated by the capacitance to a point where it is now a series resonant circuit "C". We know the inductive reactance ( it is the resistance offered by an inductor) XL=2πfL.

Typical moulded chokes which can be purchased fairly cheaply aren't exactly designed to be monuments to either high "Q", thermal stability or high tolerances.

One exception might be applications involving either non-critical high pass filters or low pass filters. and it should appear like this: Also remember the higher the permeability of the core the less turns required and the less "distributed capacitance" appearing in your chokes. It is used to filtrate output of Rectifier and provide pure DC output. The resistance is the inherent resistance in the choke both at ac and dc.

Now a day’s Electronic Choke is used in Fluorescent tube light.

As a choke coil is an inductor so it tries to block the AC current but in the case of DC it does not give any resistance to flow of DC current.

The choke's impedance increases with frequency.

visit Ian Purdie VK2TIP's "Chokes" Page,
Another typical use would be to feed DC power into an RF amplifier of some type. It is used in the devices which are used in radio stations. You could in some very casual applications substitute chokes for fixed inductors but as a general rule and of course there are exceptions to this rule, I wouldn't. At higher frequencies consider a small air wound choke. Why Choke coil used in Fluorescent tube light? Most important!, you don't want it functioning as a "flash" fuse, pun intended.


A choke coil stores electrical charge by creating a magnetic field around it.

The difference between the balanced twisted windings CM choke and conventional balanced two winding CM choke is that the windings interact in the center of the core open window. be identified as the author of this web site and all contents herein.

Please visit VK2TIP's Book Shelf. A choke usually consists of a coil of insulated wire often wound on a magnetic core, although some consist of a doughnut-shaped "bead" of ferrite material strung on a wire.

To reduce the near magnetic field emission, a twisted winding structure can be applied to the CM choke.

Its low electrical resistance passes both AC and DC with little power loss, but its reactance limits the amount of AC passed.