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Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets.

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Old 19th Jul 2017, 2:58 am   #21
Synchrodyne
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Default Re: Lesson R,L,C,T,V,D but Q and U ?

Possibly Toshiba used "S" for silicon-based device? But if so, we might also expect to find "G" for germanium.

In the early Sony case, I imagine that "X" was for Xtal = crystal triode.

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Old 19th Jul 2017, 4:12 am   #22
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Default Re: Lesson R,L,C,T,V,D but Q and U ?

S for Semiconductor? In the thermionic era, "V" included diodes, so perhaps an updated counterpart seemed apposite.
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Old 19th Jul 2017, 10:38 pm   #23
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Default Re: Lesson R,L,C,T,V,D but Q and U ?

Ah yes, “S” for semiconductor seems more logical than “S” for silicon.

So far, the above-mentioned Lin quasi-complementary article remains the earliest I can find where transistors are designated with “Q”. Thereafter “Electronics” magazine often used “Q”, but not exclusively so, sometimes using “T”. Some RCA publications after that date also used “T”. So, there do not appear to have been editorial decisions by “Electronics” or RCA to standardize on “Q”.

Possibly it came from RETMA or the US Military, as one imagines that the latter would want to have standardized schematics. Or as a “left-field” idea, perhaps it was simply caprice on Lin’s part, taking the “Q” from quasi, with others then following what seemed like a good idea.

But then I’m thinking that when the answer does turn up, it will be “none of the above”.

The Lin quasi-complementary circuit was certainly a landmark, although I am not sure that it was intended as such, but more as another approach, and as part of a complete gramophone amplifier. Fully complementary circuits had been proposed several years earlier. It’s interesting too that improvements to the Lin circuit to correct its inherent asymmetry were not developed until the end of the 1960s; of these the Baxandall diode was the definitive version.

Notwithstanding the widespread use of “Q” in American practice, one does find variations. Here is an odd case from an early 1970s Sylvania TV receiver, in which “Q” was used for the VHF tuner, but “T” for the UHF tuner. (The main chassis used “Q”.):

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Possibly the UHF tuner was outsourced from an assembly maker who preferred to use “T” rather than “Q”, and Sylvania opted not to transcribe the schematic, but then they do appear to have been designed to work with each other. They were early varicap units. Thus, one sees an RF amplifier in the UHF tuner, hitherto very unusual in American practice, but probably added to offset varicap losses. The VHF tuner was “transitional”, with a fet RF amplifier but a bipolar cascode mixer, a stepping stone to all-fet designs. Apparently with varicap tuning it was more convenient to inject IF from the UHF tuner into the VHF mixer rather than into the VHF RF amplifier as had been past American practice, so more gain was required from the UHF tuner, in this case obtained by the use of an active mixer in place of the customary diode. (Other makers kept the diode and added an IF stage within the tuner.)

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Old 24th Jul 2017, 4:43 pm   #24
M0ALK Richard
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Default Re: Lesson R,L,C,T,V,D but Q and U ?

https://electronics.stackexchange.co...r-transistor-q
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Old 25th Jul 2017, 12:05 am   #25
Synchrodyne
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Default Re: Lesson R,L,C,T,V,D but Q and U ?

The notion that the “Q” symbol stems from the shape of the TO18 case might run into a chronology difficulty. We can trace use of “Q” back to at least mid-1956. On the other hand, a preliminary search finds no reference to TO18 earlier than the 1960s.

Perversely, something I did come across was the use of “T” for tube in a 1951 article that was written by a RCA staffer:

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Old 25th Jul 2017, 12:32 pm   #26
emeritus
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Default Re: Lesson R,L,C,T,V,D but Q and U ?

Although the TO18 designation may not have been introduced until the 1960's, the case style itself was in use somewhat earlier. It is shown in the attached Texas Instruments (UK) leaflet dated February 1958, which describes and illustrates their first UK-manufactured silicon devices that were already in production at that date. It can safely be assumed that such devices would have been manufactured and sold in the USA in 1957 or earlier. No designations are given for the various case types.
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File Type: pdf TI Leaflet Feb 1958.pdf (1.00 MB, 22 views)

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Old 25th Jul 2017, 12:50 pm   #27
ms660
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Default Re: Lesson R,L,C,T,V,D but Q and U ?

The Regency TR-1 used X.

Lawrence.
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Old 26th Jul 2017, 12:12 am   #28
Synchrodyne
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Default Re: Lesson R,L,C,T,V,D but Q and U ?

Quote:
Originally Posted by emeritus View Post
Although the TO18 designation may not have been introduced until the 1960's, the case style itself was in use somewhat earlier. It is shown in the attached Texas Instruments (UK) leaflet dated February 1958, which describes and illustrates their first UK-manufactured silicon devices that were already in production at that date. It can safely be assumed that such devices would have been manufactured and sold in the USA in 1957 or earlier. No designations are given for the various case types.
Thanks for that. Consequent further searching turns up the JETEC (when did it become JEDEC?) TO-5 Outline with JETEC E3-44 base, also of Q-form. This is shown for example in GE Transistor Manual 3rd Edition, 1958 (http://chiclassiccomp.org/docs/conte...dEdition.pdf):

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This manual included a listing of all JETEC-registered transistors from all makers.

The GE Transistor Manual 2nd edition (http://n4trb.com/AmateurRadio/Semico...nd_Edition.pdf), also included a full JETEC-registered listing. But none of the associated outline drawings had any JETEC designations, nor did any show the Q-form base. That of course does not preclude the possibility that the Q-form base was already being used for non-JETEC registered transistors.

There was no apparent date on the 2nd edition, but the 7th edition in 1964 (http://www.introni.it/pdf/GE%20-%20T...ual%201964.pdf) notes that the series was first published in 1957. So the first three editions were issued in the 1957-58 period.

Anyway, we may now date the Q-form base back to 1957-58, close to the 1956 putative first use of the “Q” symbol on schematics. The Lin QC circuit used 2N109 output transistors, and these did not have a Q-form base.

In the 2nd and 3rd editions of the GE Manual, the symbol “TR” was used on schematics. But “Q” was used in the 7th edition.

Quote:
Originally Posted by ms660 View Post
The Regency TR-1 used X.
As far as I know, the Regency TR-1 used a TI circuit, so perhaps “X” was TI’s symbol.


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