Origin of 'condenser' name

[paulsherwin]

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

[G8HQP Dave]

Storing a lot of charge in a small space? That is a bit like condensing a gas to make a liquid. Just a wild guess.

[Paul_RK]

Originally Posted by G8HQP Dave

That is a bit like condensing a gas to make a liquid. Just a wild guess.

An accurate guess at Volta's reasoning for adopting the term: the OED's first recorded use of it is in a paper he published in 1782.

Paul

[G6Tanuki]

Yes, at one time electricity was thought of as an invisible 'vital fluid' and the likes of the Leyden Jar [an early capacitor] were used to store it!

[This is I guess also where the old unit-of-capacitance called the "Jar" came from?]

[Skywave]

I've always understood the word 'condenser' arising by analogy to condensation of water molecules on a cold window in a warm room. However, if the temperature changes so that the outside of the window becomes warmer than the inside, the reverse takes place. Thus there appears to be a movement of water molecules through the glass dielectric, which is not actually the case. What does happen in the above scenario is that water molecules become stored on one side of the window or the other. So, in conclusion, the capacitor 'condenses' the electrons and in the above window analogy, the glass acts as the dielectric in a capacitor.

Al.

[paulsherwin]

Interesting that the term goes back to Volta. I was thinking it was from the Maxwell era.

[Al (astral highway)]

Originally Posted by paulsherwin

Can anyone explain the origin of the term 'condenser' for a capacitor? What is it 'condensing'?

Hi Paul,

The originator of the invention was Pieter van Musschenbroek, a Dutch polymath. He lived in Leiden (correct spelling) and after he described his experiments to another scientist in a letter, and the letter was translated shortly afterwards, the name was transliterated to 'Leyden' jar, after his place of origin. The idea took hold in 1746, way before Volta contributed to science with his Voltaic pile.
Van Musschenbroek was contemporary with Newton, and even attended his lectures.

For Van Musschenbroek, it was a natural extension of his original research into electrostatics that took him in the direction of looking for a way to store electrical charge. He had already contributed to the refinement of machines that could create electrostatic charge, without storing it.

Van Musschenbroek and a German contemporary of his (who actually pipped him to the post in terms of the discovery) both clearly knew that charge was being concentrated into a small space by the 'Leyden' jar, where it could do work if an external circuit was completed.

This concept of confinement of a charge remained intact in the English formulation, condenser. It had been there from the beginning...

[Paul_RK]

There seems to have been some uncertainty as to what to use the word for at least until Maxwell's day...

"I had rather call it a condenser of electricity, using a word which expresses at once the reason and cause of the phenomenon" (Volta, 1782)

"The metal plate... does actually condense or acquire a greater quantity of electricity" (Volta, 1782)

"Accumulators are sometimes called Condensers, but I prefer to restrict the term 'condenser' to an instrument which is used not to hold elecricity but to increase its superficial density" (Maxwell, "Electricity and Magnetism", 1881)

[emeritus]

Here's the definition given in the 1911 edition of the Encyclopaedia Brittannica: The word was used in a number of different fields ito refer to concentration or intensification.

[M0FYA Andy]

In Germany the word is still used - Kondensator.

[bluepilot]

condensateur in French

[evingar]

condensatore in Italian

[Paul_RK]

And condenser in The Radiophile

[Al (astral highway)]

Kонденсатор ='Condensator,' likewise, in Russian.

[emeritus]

Condensador in Spanish.

[SiriusHardware]

I've always thought that 'condenser' was also the standard term for a capacitor in American English, and even in the UK it is still sometimes preferred over the term 'capacitor' whenever capacitors are referred to in an automotive context.

[M0FYA Andy]

With my main vintage electronic interest being in aircraft equipment from the WW2-era, where all the documentation uses 'condenser', I tend to use both words at random!
I've always though 'capacitor' was imported from America. If not, where did it come from?
Andy

[paulsherwin]

I also thought 'capacitor' became the preferred term in America before it did in Britain. Would an American member like to comment?

In Britain the change of terminology seemed to happen in the 50s. You rarely find transistor circuits described as using condensers.

[Station X]

My mid 1960's text book says "Capacitor or condenser" with a foot note saying "Capacitor is recommended by the British Standards Institution, but the term 'condenser' is still widely used".

Resistors have resistance.
Inductors have inductance.
Condensers have condensance

When I hear the word condenser I immediately think of the part of a steam engine which condenses steam back into water.

[russell_w_b]

Originally Posted by M0FYA Andy

With my main vintage electronic interest being in aircraft equipment from the WW2-era...

The 1943 Technical Glossary for BBC Engineers has, under condenser: 'see capacitor'.

When looking up 'capacitor' it has 'condenser' in brackets. So the BBC back in '43 were moving over to 'capacitor' as the descriptor of choice. Instruction TT5 (1944) on MW matching networks still refers to condensers, however.

Atkinson, in his 1947 book 'Telephony' uses 'condenser' primarily but has 'capacitor' in brackets afterwards. So it looks like the British were being gradually nudged over to 'capacitor' in the 1940s: a very, very, gradual nudge...

I get the impression from the Admiralty Handbook that 'condense' in condenser is used in the sense like making denser or more concentrated: 'the charge which a body can hold for a given potential may be increased by concentrating the region over which its field extends...'

A 'Jar', incidentally, does originate with the Leyden Jar, and 1 Jar = 1.11111nF (1nF = 0.9 Jars). The Jar was discontinued in 1938, having been deemed obsolete for a few years previous to then.