# Using the word tension in place of voltage

I was reading this paper on electrolysis and on page 2 on the third line of the second paragraph it reads:

In each cell there will be a tension of 4.5 volts and a current of 25 amperes will pass;

While it may be obvious that tension would mean voltage, I'm curious as to why that would be the case?

I'm also seeing it in this blog describing an LM741

When the power supply is tuned to the maximum, it will output almost V+ (9 V). At the minimum, almost V- (0 V). Between the two, it can output any tension (1.3 V, 2 V, 4.73 V, 6.89 V...). The adjustment of the power supply can change from the minimum to the maximum in about one millionth of a second.

• Wiki page on voltage for reference. The word 'tension' is still encountered: as in high-tension transmission lines etc, but it is rare for it to be used in Electronics textbooks anymore.
– Syed
Jan 26 at 13:00
• If you are not aware, the French use tension for voltage so that is another link - apart from the use @Syed points out. And then they use U for the symbol… Engineers are short of letters for naming things so some get used for several things - which means you have to understand what you are working with… Confusing U for U between tension aka volts when it is acceleration :) Jan 26 at 13:06
• Similarly, the Nordic languages uses the equivalent word for tension/excitement too (sw:"spänning"/ no:"spenning" / dk:"spænding") when speaking of voltages. Jan 26 at 13:14
• @Lundin Add German to this list (Spannung). Maybe English is really the odd one :) Jan 26 at 13:23
• @TypeIA Seems Italians use voltaggio - the unit is named after the Italian Alessandro Volta. Jan 26 at 13:30

I'm going to refer to voltage as "tension" throughout this answer.

The English word "tension" (in the electrical sense) is much older than "voltage," and it was probably used long before scientists were able to formulate a clear definition of tension.

Alessandro Volta certainly had some idea of tension. A handful of sources on the Internet say that Volta described a law of capacitance (stating that in a capacitor, tension is proportional to charge) in 1776. I haven't been able to find any primary sources for this, and I have no idea whether he used the word "tension," or a different word like "potential." In any case, he certainly never called it "voltage."

Michael Faraday published a book titled Experimental Researches in Electricity in 1839. The book uses the word "tension" in a few different places. For example, in the section "Identity of Electricities derived from Different Sources," Faraday writes:

Tension.—When a voltaic battery of 100 pairs of plates has its extremities examined by the ordinary electrometer, it is well known that they are found positive and negative, the gold leaves at the same extremity repelling each other, the gold leaves at different extremities attracting each other, even when half an inch or more of air intervenes.

That ordinary electricity is discharged by points with facility through air; that it is readily transmitted through highly rarefied air; and also through heated air, as for instance a flame; is due to its high tension.

It's not obvious exactly why Faraday chose to use the word "tension" rather than some other word, but he was probably imitating earlier authors. I don't think Faraday had a very clear idea of just what tension is.

In the year 1861, Latimer Clark and Sir Charles Bright proposed a unit of measurement for what they called "electrical tension, potential or electromotive force," in their paper "Measurement of electrical quantities and resistance." Their proposed unit was the "ohma," and it never caught on.

No later than 1873, as described in the Wikipedia article "Volt," a new measurement of tension had been defined, and, as you know, this new measurement was called a "volt." I haven't been able to find where the idea for a volt came from, though.

Finally, since the unit of electric tension was called a volt, speakers of English started to refer to tension as "voltage" instead. (The Online Etymology Dictionary says that the word is from 1882, but doesn't give a source.) For one reason or another, the word "voltage" ended up becoming so popular that the older word, "tension," has been all but forgotten.

(As TypeIA mentioned in a comment, English is pretty much the only European language that uses a word similar to "voltage." Most other languages use either a word related to "tension," or a completely different word like "napięcie.")

• "napięcie" is not a completely different word. It is a literal translation of "tension". Jan 27 at 1:38

As for the first article, although the date isn't clearly mentioned, it dates from 1911 apparently. Wordage has evolved since.

As for the second article, it is written by a French person (Eric Brasseur). In French, especially in academics, voltage is most often referred to using the word "tension". "Voltage" in French sounds awkward, just like saying "amperage" instead of "current". So it is simply a mistranslation.

In short: those two examples are not very representative.

• Not just French, also many, maybe even most European languages including German, Spanish, Italian, Dutch, Danish, Swedish, Norwegian, etc. all use the same word for tension and voltage. Jan 26 at 13:27
• I second the above. "Voltaggio" (~= voltage) in Italian does not just sound awkward, it is just plain wrong and it is considered a layman term. Jan 26 at 13:30
• @VladimirCravero Do you speak Italian? If so I'll delete my comment to the question above, it was a google translate. Italian in particular is interesting because of Alessandro Volta. What is used if not "voltaggio"? Jan 26 at 15:32
• I indeed speak Italian - it is my mother tongue language. A. Volta gives the name to the SI unit Volt, but we use "tensione". Again, some people do use it, but definitely not in the ee industry. @Lundin Jan 26 at 16:22
• As an aside, If you run into a native romance language speaker who uses tension for voltage when writing English, they're likely to also use intensity for current. Jan 26 at 16:35

Complementing other's answers, even the term "voltage" is used imprecisely. What we associate with that term is more precisely described as "voltage difference" or "electric potential difference". Since in most practical applications the voltage is measured against a local reference, the difference in usage of the terms is mostly academical.

Expanding on Tanner Swett's answer, in Brazilian Portuguese we use voltage, tension, electromotive force (usually in the context of motors) and, rarely nowadays, DDP (Portuguese acronym for potential difference) interchangeably.

It's not unique. You might compare current (equivalent to tension in a linguistic sense), measured in amps (equivalent to volts). Amperage hasn't taken over from current, unlike voltage taking over from tension, but just as amperage was formed from amp(ere)s, voltage was formed from volts.

Power and wattage work similarly to current, but much more in an electrical sense than in the sense of mechanical or thermal (except electric heaters) power. We never see *newtonage for force or *joulage for energy, for example, so this quirk of technical English appears to be at the interface between Physics and Electrical Engineering - not that the latter was a distinct discipline when the terms were coined; it probably was by the time they became commonplace.