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srinath 13th December 2012 07:51 PM

What does +3v3a mean in a schematic
What does "3v3a" mean in a schematic, I see it next to a connector like it comes out of the rectifier bridge then the smoothing caps etc then it says +3v3a. I also see it in - else where, and I see +5vd or +5VV or -5VV ...

What does that mean exactly.

Thanks in advance.

Frank Berry 13th December 2012 07:54 PM

3 volts @ 3 amps perhaps.
Please tell us more. What schematic? What is the piece of equipment?

nattawa 13th December 2012 08:54 PM

In a digital/analog mixed system it usually means a supply rail of +3.3V filtered/regulated for Analog sections.

srinath 14th December 2012 12:11 AM

OK cool, 3.3 v analog and 3.3 v digital, but what is a 5 vv - 5v I get, what is the second v.
The receiver is a Harman kardon avr 7000. The schematic is on electrotanya or on google on several places, or I can put 1 page of it here - not the whole thing, too big I think.

TANDBERGEREN 14th December 2012 12:33 AM

Often such extra suffixes on explanationpoints as theese is made to be able to know different voltage sources from each other.
There is several reasons why manufacturers wants to have separate voltage sources such as better noisecancelling, reducing crosstalk and so on.
Been looking at the AVR 7200, but of course, there they have a different structure on it all.

Been looking through the rev 3 and 4 now.

I find .3V3A and +3V3D, in addition to +5VA and +5VD
The suffixes A and D is clearly for Analogue and Digital.
A relatively sensible way to separate the, I think.
+5vv may be to make the technician absolutely sure he is on the right +5V rail somewhere in the schematics.
It's really huge.

srinath 14th December 2012 12:48 AM

Yes that was my guess, its 3.3v but this is 3.3 v from the d source, that other one is the c source and the a source is different from it all. That was my first guess ... see the 10,000 mf cap blew in the supply line to the other caps on the other board.

7200 is pretty close to the 7000 I htink, we can put our heads together and help each other maybe ... so what is wrong on yours.


srinath 24th December 2012 08:05 AM

And what does a darker line mean on the schematic ?
It seems to be the sound path, like L-IN and L-OUT but doesn't follow all the sound - like not for C-IN or C-out.

I also see protect circuit gets to that dark line. What is the exact significance of that line being darker ?

burbeck 24th December 2012 10:28 AM

3V3A, is generally taken to mean 3.3 VA
In the same way:-
4V7 = 4.7 V
5K6 ohm = 5.6k ohm = 5600 ohm
4V7A. = 4.7 VA
4m7H = 4.7mH
This is Europe standard , where the decimal point is swapped for the units multiplier, I would guess this was introduced to reduce the number of markings on components as they get smaller, and to avoid using a "dot" which is difficult to see.For instance a zener diode 8.2 volts, 1.3W ,Would be marked as 8V2 1W3

jaycee 24th December 2012 10:43 AM

if it is on a schematic referring to a power supply rail, I take it to mean +3.3V analogue, meaning 3.3v used for analogue circuitry power, seperated from digital.

srinath 24th December 2012 01:27 PM

I think I may have seen a VV in it, I cant look for it right now.
This amp I have to think the problem is in the supply board, I am going to get back to it tomorow.

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