Hi all,

I am trying to understand the preference between a choke and inductor in a DC to DC converter and a DC to AC inverter. Is a choke always used on the input side and an inductor/reactor on the output of the DC to AC converter if it is grid tied.

Thanks!

 

A choke is just a type of inductor.
It usually has a high inductance with a specific a function, which is often to significantly attenuate high frequencies, hence its name.

In general, an inductor has a specific inductance to perform other functions such as filtering certain frequencies or temporary energy storage in power converters.

 

One often seen in older mains fed DC supplies was the Pi Filter and proved quite efficient.

 

Two names for the same thing, like condensor and capacitor.

 

Two names for the same thing, like condensor and capacitor.

That's not an exact analogy, as all condensers are capacitors, but not all inductors are chokes (expect in a very loose sense of the term).

A better analogy might be automobile and vehicle.

 

That's not an exact analogy, as all condensers are capacitors, but not all inductors are chokes (expect in a very loose sense of the term).

A better analogy might be automobile and vehicle.

+1
You often see chokes and inductors working together in a typical RF amplifier. The choke separates the generated RF from the DC/AC supply bus and the inductor tunes the RF output.



https://www.ctrengineeringinc.com/rf-chokes-and-inductors/

 

All the references I have checked seem to be struggling to identify a difference. For instance, if

The choke separates the generated RF from the DC/AC supply bus and the inductor tunes the RF output.

why is there DC on the antenna? That final choke connected to the antenna looks much more as though it is part of a tuned circuit, which would fit your definition of an inductor.

Wikipedia gets itself into a complete muddle

The name comes from blocking—"choking"—high frequencies while passing low frequencies. It is a functional name; the name "choke" is used if an inductor is used for blocking or decoupling higher frequencies, but the component is simply called an "inductor" if used in electronic filters or tuned circuits. Inductors designed for use as chokes are usually distinguished by not having low-loss construction (high Q factor) required in inductors used in tuned circuits and filtering applications.

so it's a choke if it blocks high frequencies and passes low frequencies (i.e. a filter) but an inductor if used in "filtering applications"?

OED gives "choke" as an abbreviation of "choking coil"

2. choking coil n. a coil of high inductance inserted in an alternating-current circuit to impede and cut down the current or to change its phase. Called also impedance or reactance coil.
1893 R. M. Walmsley Wormell's Electr. in Service of Man 644 An extremely pretty device known as a ‘choking’ coil.
1902 W. G. Rhodes Alternating Currents 83 Impedance coils, or choking coils, as they are often called, are simply coils having low ohmic resistance and high self-induction.
1962 S. Handel Dict. Electronics 52 Choke (Choking coil), an inductor designed to present a relatively high impedance to alternating current.

and inductor:

d. A device (commonly a coil) possessing inductance or used on account of its inductance.
1928 G. E. Sterling & R. S. Kruse Radio Man. i. 20 Iron Core Inductance.—This form of inductor is made by winding many turns of wire on an iron core.
1950 K. Henney Radio Engin. Handbk. (ed. 4) iii. 124 Straight wires are used as inductors in h-f applications where the inductance must be very low.
1963 G. E. Williams & B. J. Prigmore Electr. Engin. v. 129 A standard mutual inductor..can be made by winding coil No. 1 on a long straight core and winding No. 2 round the mid-portion of No. 1.

Perhaps the best definition is that a choke is for power and an inductor is for signals. In which case, in the context of the original question, they are all chokes.

 

Perhaps the best definition is that a choke is for power and an inductor is for signals. In which case, in the context of the original question, they are all chokes.

That's also an inaccurate distinction.
Inductors are often used for power purposes, such as switching power supplies.

A choke is usually used in RF applications to essentially block the RF signal, but it's not a tuned circuit, i.e. a specific inductor value with a specific capacitor value.
RF inductors are usually used in a tuned circuit.

 

All the references I have checked seem to be struggling to identify a difference. For instance, if

why is there DC on the antenna? That final choke connected to the antenna looks much more as though it is part of a tuned circuit, which would fit your definition of an inductor.

Why is there DC on a antenna? Because big HF antennas are outside with the wind, dust and weather can produce large triboelectric effect static charges. Touching a ungrounded antenna can be a shocking experience. The choke is there is bleed that static to ground and is a safety factor in the rare case of HV tube coupling capacitor failure.
https://palomar-engineers.com/antenna-products/antenna-static-bleeders/
https://www.edn.com/rf-power-amplifier-safety/

 

That's not an exact analogy, as all condensers are capacitors, but not all inductors are chokes (expect in a very loose sense of the term).

A better analogy might be automobile and vehicle.

NONE of the condensers on my refrigeration systems are capacitors. "Choke" is an application description for an inductance used to resist the flow of alternating current, usually in a DC circuit..

 

https://info.triadmagnetics.com/blog/chokes-vs-inductors-whats-the-difference

"all chokes are inductors, but not all inductors are chokes"

 

But what is in the set of “inductors that are not chokes”?
The only thing I have found consistently to be named “inductor” but never “choke” are inductors in tuned circuits of radio equipment.
Resonant power supplies use both terms interchangeably for the “resonant” inductor.
Buck regulators use both terms for the output inductor.
Radio Frequency Chokes are used on both AC and DC signals.

 

NONE of the condensers on my refrigeration systems are capacitors

Okay, I'm sure you know what I was referring to, but to be pedantically correct, I was referring to electrical condensers.

 

NONE of the condensers on my refrigeration systems are capacitors.

And I bet that its compressor doesn’t do a great job at keeping your hi-fi sound level constant!

 

The people that design, manufacture and sell Chokes, Reactors (don't forget reactors) and Inductors to engineering specifications know what is what.
https://www.ato.com/difference-between-reactor-and-inductor

 

The people that design, manufacture and sell Chokes, Reactors (don't forget reactors) and Inductors to engineering specifications know what is what.
https://www.ato.com/difference-between-reactor-and-inductor

It was written by someone whose first language was not English. "The inductor is also named as the choker"!
We buy lots of high-power inductors and our supplier calls them "chokes".