What does VT stand for?

[Craig Sawyers]

In older circuit schematics transistors are often numbered with the prefix VT. Later of course common usage moved to Tr.

Does anyone know what VT stood for?

Cheers

Craig

[ms660]

Valve Transistor?

Mag page 125/126:

https://www.americanradiohistory.com...ld-1955-03.pdf

Lawrence.

[Craig Sawyers]

Absolutely awesome! Well done in finding probably the first reference to using VT - for Valve Transistor.

I've no idea how you found the particular issue of WW that mentioned that!

Cheers

Craig

[M0FYA Andy]

It's interesting that in the circuit a couple of pages earlier in that WW the transistors are labelled V1, V2 etc!

[paulsherwin]

I vaguely remember that 'CT' was used in a few early circuit diagrams - Crystal Triode.

[David G4EBT]

More puzzling (to me at any rate), is why 'Q' - as in Q1, Q2, Q3 etc?

I saw packs of 20 Mullard 'red spot' transistors for £1.00 on John Birkitt's stall at a rally.

How times change - back in 1960 they were ten shillings each, equivalent to £11.00 today!

That circuit which Lawrence pointed to looked intriguing - wind your own coils/transformers. I wonder how it performed?

['LIVEWIRE?']

Radiomobile always used 'VT' in their diagrams during the 60s & 70s-did it mean 'Valve Transistor'? I never knew! As to 'Q' this was common practice on American Circuit diagrams, but, again, I never knew the reason.

[Craig Sawyers]

Maybe the US guys used sequential single letters for different components?

Q - Transistor, R - Resistor, S - Switch(?), T - Transformer(?), U - Integrated Circuit (eventually).

Just a guess, really.

Craig

[ukcol]

Originally Posted by David G4EBT

More puzzling (to me at any rate), is why 'Q' - as in Q1, Q2, Q3 etc?

I couldn't find a definitive answer to why "Q" was used for a transistor but the most common answer I came across was simply that Q had not previously been assigned to something else, it was sort of "left over" waiting to be used.

One thing that is frustrating about finding information on the net is that there are so many forums full of different peoples "guesses" as to the answer to a question with no supporting evidence offered.

[Craig Sawyers]

This seems as definitive as it comes with web information https://www.electronics-notes.com/ar...s-overview.php

Seems like Q (and other things like U for integrated circuits) was defined in IEEE and ASME standards.

Craig

[Herald1360]

My guess (sic) is that the U derived from the common substitution of u for mu used as symbol for micro and the association with microcircuit.

[David G4EBT]

Originally Posted by Craig Sawyers

This seems as definitive as it comes with web information https://www.electronics-notes.com/ar...s-overview.php

Seems like Q (and other things like U for integrated circuits) was defined in IEEE and ASME standards.

Craig

That's a useful link Craig - thanks.

['LIVEWIRE?']

Another puzzle is 'why 'L' for inductors. H would surely have been more logical

[Skywave]

Thinking in terms of very early wireless, L for loading (coil)?
Or L for linkages - as in magnetic flux lines? (That probably dates back even earlier).

Al.

[Herald1360]

Originally Posted by 'LIVEWIRE?'

Another puzzle is 'why 'L' for inductors. H would surely have been more logical

Perhaps I?
Resistor
Capacitor (ondenser)
Inductor

But quite a long time pre wireless, loading coils were used on telegraph/telephone lines to turn them into lumped L distributed C transmission lines.

[FrankB]

VT= Vacuum Tube. (You folks would call it a Valve)

There were massive amounts of odd naming of components.

The latest I saw was PCE/Magnavox/sylvania/ Crosley/ Phillips naming parts on the board with 4 numbers on TV sets here in the U.S. You had to have the OEM svc. manual to figure out what they were if they were crisped.

Craig hit it on the head. T or TX for transformer, unless it was a flyback then you might see FBT used.
Y= Yoke
R= Resistor
C= Capacitor/ condenser
Q= Transistor, but I have seen TR used also. And to yet further confuse the techs, I have
seen them called T, and VT. ( When I saw one of the earlier Asian made transistor
radios it used VT for the transistor designation.) Sigh....................
I= Inductor, except when they called it "T".

I think they must have been drunk on their behinds for what they called some of the parts.

One of the mysteries of the world that we may really never know the answer to.

[G6Tanuki]

Must admit, if faced with a device whose identity started "VT" I'd instinctively think "Valve, Transmitting", that being the prior-to-the-introduction-of-CV-standard-designation Navy nomenclature.

[VR was Valve, Receiving and VI was 'Valve, Indicating' which embraced magic-eyes and small CRTs]

[jayceebee]

Can I throw another into the mix, W for diode. I was led to believe this came from "Westector" which were early metal rectifiers, of course some manufacturers used MR for diodes also.

John.

[Leon Crampin]

For a non-American interpretation, how about "Valve, thermionic"?

Leon.

[John10b]

VT could mean Video Tape, depends who you are talking too.
Cheers
John