Re: Dumb question...what does Q stand for?

[BigBadger]

excuse my ham fistedness on the keyboard...see revised post below:

I've got a old motherboard in front of me with a burned out component.
printed on the board next to this component is 'Q7'.
Now I can figure that:
'R' means resistor,
'C' means Capacitor
'EC' means Electrolytic Capacitor,
However i can't work out what 'Q' stands for. Anybody out there who can
advise?
Thanks

Have a look at this page:
https://www.fully4world.com/pcb-printed-circuit-board-parts-and-components-identification/

Bertus

 

[Frank Bemelman]

excuse my ham fistedness on the keyboard...see revised post below:

I've got a old motherboard in front of me with a burned out component.
printed on the board next to this component is 'Q7'.
Now I can figure that:
'R' means resistor,
'C' means Capacitor
'EC' means Electrolytic Capacitor,
However i can't work out what 'Q' stands for. Anybody out there who can
advise?

Often it's a transistor or in this case probably a mosfet used
as the switcher in an on-board switched power supply. But designers
have unlimited freedom, and as such are allowed to call anything
whatever they like!

 

[Keith R. Williams]

excuse my ham fistedness on the keyboard...see revised post below:

I've got a old motherboard in front of me with a burned out component.
printed on the board next to this component is 'Q7'.
Now I can figure that:
'R' means resistor,
'C' means Capacitor
'EC' means Electrolytic Capacitor,
However i can't work out what 'Q' stands for. Anybody out there who can
advise?

Transistor.

 

[t smith]

Well obviously Q = Transistor

 

[Winfield Hill]

Keith R. Williams wrote...

BigBadger asked...

Transistor.

Q means quality factor. :>)

Thanks,
- Win

 

[The real Andy]

Keith R. Williams wrote...

Q means quality factor. :>)

Thanks,
- Win

So who came up with 'Q' for transistors?? Why not T?? (I'm guessing that's
because the transformer came before the transistor)

 

[RP Henry]

So who came up with 'Q' for transistors?? Why not T?? (I'm guessing that's
because the transformer came before the transistor)

I think there's a mil-spec for this somewhere. I remember the difficulty I
had with an older checker when I started using D instead of CR (current
rectifier?) for diodes.

Just looking at the schematics on my desk...

Why K for relays? L for inductors? U for IC's? LS for speakers? X for
sockets? Y for crystals?

 

[Alan Douglas]

Hi,

I remember the difficulty I had with an older checker when
I started using D instead of CR (current rectifier?) for diodes.

Crystal Rectifier, a term coined by George Washington Pierce of
Harvard in his 1910 text "Principles of Wireless Telegraphy."

In 1909 he proved by the use of a Braun cathode-ray oscillograph
that the rectified current did not lag the applied voltage and so
could not be a heat effect, as had been speculated. His cold-cathode
CRT was excited by a 40,000 volt storage battery.

Cheers, Alan

 

[Ben Bradley]

Q is widely used for the "quality" of tuned circuits, but it is
also often used for an inductor's "quality" and sometimes a
capacitor's "quality" as well. And that use surely predates
transistors, but Q as quality is an aspect of a component rather than
a component label.

That's always been my understanding, that there was already
something else using the most obvious letter.

I think there's a mil-spec for this somewhere. I remember the difficulty I
had with an older checker when I started using D instead of CR (current
rectifier?) for diodes.

I always thought CR was for (germanium?) "crystal rectifier" as
opposed to other types, such as selenium or copper oxide rectifiers.
Of course saying "crystal" is redundant now, as all semiconductors (in
the last several decades) are made of grown crystals of silicon.

Just looking at the schematics on my desk...

Why K for relays?

Because R was already in use for resistors, and K wasn't used for
anything else. But why K instead of A or B or E or F...

L for inductors? U for IC's?

V for tubes? (presumably for Vacuum tubes "here" or Valves across
The Pond, but which one came first?)

LS for speakers? X for
sockets? Y for crystals?

C'mon, let's go through the alphabet, Z for impedances, alpha is
for something electronic (but what?) in addition to a type of
radiation, beta is current gain, ... omega represents the unit of
resistance, named after Mr. Ohm...

 

[Frank Bemelman]

"TSmith1315" <[email protected]> schreef in bericht

[snip]

U: unnecessary digression. Excuse me it must be gettting late...

Then the Q must stand for Questionable component.