Origin of 'condenser' name

[russell_w_b]

Originally Posted by paulsherwin

'I also thought 'capacitor' became the preferred term in America before it did in Britain.'

The U.S. author Fred Terman, in his book 'Radio Engineering' (McGraw-Hill) referred to them as 'condensers' but again, in the index, there is 'condenser: see capacitor'.

[CambridgeWorks]

In 1966, our tech college instructor for C&G subject 55, radio amateurs exam made it very clear he NEVER wanted to hear us use the word "condenser", unless we were talking about steam engines!
Rob

['LIVEWIRE?']

Russell - An elderly Scotsman wth whom I worked about 46 years ago, and who had been in the Navy during WW1 used to talk of capacitance in 'Jars', but if he ever told me how the word, in that context, originated, I'd long forgotten, though i should have known the connection with the Leyden Jar. What I certainly never knew was the value of One Jar in nF..

[Herald1360]

An odd factoid- a jar is almost exactly 1000 cm

[Argus25]

I have thought at times that the word accumulator is the better word to describe a capacitor or condenser. It seems though to have been hijacked for chemically assisted charge storage, as in the Lead-Acid cell.

The reason is that a hydraulic accumulator (typically a chamber formed by a closed bore, piston and spring) has a certain rate of pressure rise for the increase in volume and it stores a volume of fluid and stores potential energy. The relation is Pressure = a constant x volume. So a very compliant accumulator chamber with a soft spring (low spring constant k) stores more volume without the pressure rising very high.

In the case of the capacitor the relation is Q = CV or put another way, capacitance is the charge to voltage ratio. And an amount of charge or volume of charge is stored and energy stored, just like the accumulator. So for a large value capacitor more charge can be stored without terminal voltage rising very high. Making of the capacitance value analogous to 1/k or the inverse of a spring constant which can be called compliance.

This makes the compliance of an accumulator chamber (storing a volume of fluid) and capacitance (storing a volume or amount of charge) a near exact analogy. As would be the compliance of say a rubber balloon that stores fluid, be analogous to capacitance.

Since hydraulic accumulators existed long before Leyden jars , "accumulator" might have been a better choice in the long run for describing the condenser.

However in chemically assisted accumulators, like batteries (unlike the hydraulic accumulator or a capacitor) the relationship is very non linear and large amounts of charge can be absorbed without a proportional increase in the terminal voltage, for example a lead acid battery being near fully discharged with a terminal voltage of 11V and fully charged when its 14.4. So the charge to voltage ratio is not a constant.

[TonyDuell]

I remember reading a chapter about electric refrigeration which was made confusing by the fact that 'condenser' was used both for the electrical component to introduce a phase shift to start the motor (i.e. a 'capacitor') and the part of the refrigeration circuit where the refrigerant gave up heat and turned into a liquid.

[tri-comp]

In Danish, same as in German: Kondensator.

[Dave Moll]

Originally Posted by Station X

Condensers have condensance

So how was the property of a condensor described? Or for that matter, what is used in the many languages that have been shown currently to use a translation thereof?

[Paul_RK]

Originally Posted by Dave Moll

So how was the property of a condensor described?

"By the Capacity of a Condenser or Cable is meant its power to receive a charge" (R.S. Culley, 1863)

"The term 'capacitance' is suggested as preferable to the already existing 'capacity'" (Transactions of the American Institute of Electrical Engineers, 1893).

Capacitance is what a condenser has, but then inductance is what a choke has, so where's the problem?

Paul

[M0FYA Andy]

In the Air Ministry documentation of the 40's, a resistor is often referred to as 'a resistance', and an inductor as 'an inductance'. So the words we now use to describe the electrical property of the component were the names of the components. I wonder which words the folk working on the equipment used? (The polite ones, that is! Mind you, if the films of the period are anything to go by, everybody was terribly polite at all times, even when being shot at..........)
Andy

[russell_w_b]

All the texts I have hitherto described refer to the condenser exhibiting 'capacitance' or 'capacitive reactance'.

[M0SOE_Bruce]

In "Practical Wireless Telegraphy", published 1921, Elmer Bucher refers to capacity as the property by which energy can be stored in electrostatic form. The device for storing the energy is known as a condenser (with an 'er' ending).

Similar description in "Elements for Radio Communication",1923 by E.W. Stone.

Perhaps because this technology was in it's infancy standards weren't yet adopted. Wireless signals still travelled through the "Aether".

[radioman]

I do know that the 'Trader' service sheets changed to using the word 'Capacitor' instead of 'Condenser' with sheet number 690 (Wartime Civilian receiver - battery version) in Sept. 1944.

Andy

[Skywave]

Originally Posted by Station X

Resistors have resistance.
Inductors have inductance.
Condensers have condensance

O.K., how about this for an explanation:

Resistors resist;
Inductors induce;
Condensers . . . . condense.

'Condense' in the sense of increasing the density of something - in this case, electrons that were freely moving in a conductor but on account of the condenser are brought to rest on one plate of that condenser, so their density (electrons per cubic unit) are thus increased.

Al.

[Station X]

It was a rhetorical question.

Electrical condensers and capacitors both have capacitance.

[Herald1360]

I wonder if this thread could usefully be condensed?

[Graham G3ZVT]

Originally Posted by paulsherwin

Can anyone explain the origin of the term 'condenser' for a capacitor? What is it 'condensing'? Surely they just store static charge.

I believe Paul, the definitive answer is here, at 20min 00sec.

http://www.dailymotion.com/video/x5ouo7r

I've just discovered that even in Italian you can say "capacitore" instead of "condensatore", at least according to this page:
http://www.copernico.bo.it/sito_old/.../capacita.html

Curiously I've found a thread on an Italian forum, asking the same question:
http://www.electroyou.it/forum/viewtopic.php?t=34172

[kalee20]

Originally Posted by Argus25

I have thought at times that the word accumulator is the better word to describe a capacitor or condenser. It seems though to have been hijacked for chemically assisted charge storage, as in the Lead-Acid cell.

The reason is that a hydraulic accumulator (typically a chamber formed by a closed bore, piston and spring) has a certain rate of pressure rise for the increase in volume and it stores a volume of fluid and stores potential energy. The relation is Pressure = a constant x volume. So a very compliant accumulator chamber with a soft spring (low spring constant k) stores more volume without the pressure rising very high.

True, but some hydraulic accumulators have a chamber, a piston, with a thumping big weight on top (such as was used at Tower Bridge, London). So fluid is stored at virtually constant pressure - and this is analogous to an electrical accumulator which stores charge at constant voltage.

I'd not be a fan of using 'accumulator' to describe the capacitor/condenser thingy, there's rather a significant difference!

Interesting the use of both -or and -er endings in the above sentence, too...

I have used the terms 'resistance' whereas I now use 'resistor'. I have used 'condenser'. But that's a reflection of what I used to read as a teenager I the 1970's. Why did the English world change? Dunno! I can see justification for 'condenser' occasionally, such as a photoflash energy-storage device, even if not for the gizmo that couples the AF from an anode to the following grid!

[Skywave]

Originally Posted by kalee20

I have used the terms 'resistance', whereas I now use 'resistor'.

I use both, dependant on the sentence. 'Resistor' is a noun; 'resistance' is an adjective (unless spelt with a capital R, as in 'The French Resistance') - and, IMHO, should only be used as such. E.g. The resistance of this resistor is 10 Ohms.

Al.