Vcc = Vdd ?
Archiver
Posts: 46,084
Just curious.......
Vss always seems to indicate a system ground. Whereas, Vcc and Vdd seem to be
used interchangeably to indicate a voltage above ground.
Q Can anyone shed any light on the origins of Vcc and Vdd and whether or not
there is a practical distinction between them?
Sean
[noparse][[/noparse]Non-text portions of this message have been removed]
Vss always seems to indicate a system ground. Whereas, Vcc and Vdd seem to be
used interchangeably to indicate a voltage above ground.
Q Can anyone shed any light on the origins of Vcc and Vdd and whether or not
there is a practical distinction between them?
Sean
[noparse][[/noparse]Non-text portions of this message have been removed]
Comments
not there is a practical distinction between them?
>
I'll try this one. I may be wrong, but with TTL (transistor-transistor
logic), Vcc
indicated the collector voltage source. With CMOS, Vdd indicates the drain
voltage
source. Assuming conventional current flow, that is.
Do I get a cigar?
Carl
You get a cigar! Vcc (Collector) is made positve with respect to Vee (emitter)
whereas VDD (Drain) is made positve with respect to VSS (source)
-Randy Knutson
carl@g... wrote: >Q Can anyone shed any light on the origins of Vcc and
Vdd and whether or
not there is a practical distinction between them?
>
I'll try this one. I may be wrong, but with TTL (transistor-transistor
logic), Vcc
indicated the collector voltage source. With CMOS, Vdd indicates the drain
voltage
source. Assuming conventional current flow, that is.
Do I get a cigar?
Carl
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[noparse][[/noparse]Non-text portions of this message have been removed]
(Drain) is made positive with respect to VSS (source)
Thanks Carl & Randy,
Knew there had to be a simple reason.
Sean
Vcc is applied to Bipolar based electronics.
Think Vdd and Drain, Vcc and Collector.
--
> From: "Sean Gibson" <seangib@r...>
> Reply-To: basicstamps@yahoogroups.com
> Date: Sun, 2 Jun 2002 17:38:25 -0400
> To: <basicstamps@yahoogroups.com>
> Cc: "Sean Gibson" <seangib@r...>
> Subject: [noparse][[/noparse]basicstamps] Vcc = Vdd ?
>
> Just curious.......
>
> Vss always seems to indicate a system ground. Whereas, Vcc and Vdd seem to be
> used interchangeably to indicate a voltage above ground.
>
> Q Can anyone shed any light on the origins of Vcc and Vdd and whether or not
> there is a practical distinction between them?
>
> Sean
>
>
> [noparse][[/noparse]Non-text portions of this message have been removed]
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and Body
> of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
do, that electron flow is from negative to positive. We all knew that
electrons would flow in to the emitter of an NPN transistor and out the
collector. This made sense as the collector 'collected' electrons.
Then along can this device with a source and a drain. We then, to help
us remember, said that electrons entered the device at the source and
would exit to the drain. This made sense also because ever one knows
that water flows down the drain. Also if you have a stamp board of
education Vss is clearly marked with a negative / minus sign.
HTH,
Leroy
********
> In the old days when these things were new we believed, and some still
> do, that electron flow is from negative to positive. We all knew that
> electrons would flow in to the emitter of an NPN transistor and out the
> collector. This made sense as the collector 'collected' electrons.
> Then along can this device with a source and a drain. We then, to help
> us remember, said that electrons entered the device at the source and
> would exit to the drain. This made sense also because ever one knows
> that water flows down the drain. Also if you have a stamp board of
> education Vss is clearly marked with a negative / minus sign.
negative potential to a more positive potential. You are getting
confused with "hole" migration in semiconductor materials.
Rob
Original Message
From: Leroy Hall [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=3Mej0sENBeH0Ggc47PiKafKpVwA-85ztsL2Ip7uktyTq7Gao6h3-7yL58Glh34TveIPkVe4]leroy@f...[/url
Sent: 03 June 2002 04:47
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] Vcc = Vdd ?
In the old days when these things were new we believed, and some still
do, that electron flow is from negative to positive. We all knew that
electrons would flow in to the emitter of an NPN transistor and out the
collector. This made sense as the collector 'collected' electrons.
Then along can this device with a source and a drain. We then, to help
us remember, said that electrons entered the device at the source and
would exit to the drain. This made sense also because ever one knows
that water flows down the drain. Also if you have a stamp board of
education Vss is clearly marked with a negative / minus sign.
HTH,
Leroy
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