Vcc, Vdd, Vss

[daviddoria]

what do Vcc, Vdd, and Vss mean? When is the appropriate time to use each?

thanks

david

 

[Nigel Goodwin]

what do Vcc, Vdd, and Vss mean? When is the appropriate time to use each?

I must admit, I've never really known what they stand for - but I've always presumed Vcc is the collector supply for a bipolar device (+ve voltage). Likewise Vdd is the drain supply for a CMOS device (+ve voltage) and Vss the source supply for a CMOS device (ground).

It works for me :lol:

 

[e]

Vcc = V collector, collector
Vdd = V drain, drain
Vss = V source, source

I think thats it, they represent the single side supply referenced to ground...
like Vbb = V base, base

 

[daviddoria]

so what are the 2 different things? like base, base? why isn't it just Vb?

 

[andrew2022]

so what are the 2 different things? like base, base? why isn't it just Vb?

wanted something what looked more complicated?

 

[daviddoria]

ok...
then i dont get why "voltage drain" is the +V, and "voltage source" is the ground....

 

[mrdudeman]

so a 4017 has Vss and Vdd...i connected ground to Vss and +5v to Vdd, but that seems backward to me after your explanation. it works though...umm :shock: :?

 

[mrdudeman]

ok...
then i dont get why "voltage drain" is the +V, and "voltage source" is the ground....

that is precisely where i have become confused...

 

[Nigel Goodwin]

ok...
then i dont get why "voltage drain" is the +V, and "voltage source" is the ground....

that is precisely where i have become confused...

Because on an 'N channel' FET (the most common type) the drain goes to positive, and the source goes to negative - so the drain is the equivilent of the collector, and the source the equivilent of the emitter.

 

[daviddoria]

ok... little above my head. FET is field effect transistor right? so it works similar to a normal transistor?

this is where you get the comparison of collector = drain
emmiter = source

it seems as though the collector would be the source... (like current waiting to go) and the emmiter would be the drain ( where it goes when the base is turned on)

right? how does it makes sense reversed?

 

[e]

its the source of electrons, the lower potential... who thought up this naming? hah :lol:

 

[daviddoria]

ahhh i get it

so what about Vcc ? is it the same as voltage source? cause the collector on the transistor is the same as the source on a FET, so Vcc = Vss

correct?

 

[mrdudeman]

ahhh i get it

so what about Vcc ? is it the same as voltage source? cause the collector on the transistor is the same as the source on a FET, so Vcc = Vss

correct?

i think you are correct, but it depends on the type of circuit.

 

[simoV8]

ok...
then i dont get why "voltage drain" is the +V, and "voltage source" is the ground....

that is precisely where i have become confused...

Because on an 'N channel' FET (the most common type) the drain goes to positive, and the source goes to negative - so the drain is the equivilent of the collector, and the source the equivilent of the emitter.

If the source goes to negative(vss) is that the same as return voltage??

 

[Nigel Goodwin]

If the source goes to negative(vss) is that the same as return voltage??

Sorry!, what do you mean by 'return voltage'?.

 

[Sebi]

Most of power supplyes GND marked as "return".

 

[chung lee]

Vcc, Vdd, etc

Here's the info about Vcc, etc.:

BJT FET : these are the two instances where these terms are used.
Vcc Vdd = Positive
Vee Vss = Negative/Ground

You can access this information from:
**broken link removed**

There is so much here, it could take months to go through, easily.

Chung Lee

 

[kuiy11]

what do Vcc, Vdd, and Vss mean? When is the appropriate time to use each?

Vcc is Voltage Collector Collector
Vdd is Voltage Drain Drain
Vss is Voltage Source Source
Vce is Voltage Collector Emitter
Vbe is Voltage Base Emitter
Vec is Voltage Emitter Collecter

(You better write this correctly when designing or analyzing your circuits)

(I'm not going to talk about tubes)

Why the initial duplication (Vcc; the cc)? It accommodates the naming of Voltage "potential" of the Collector, or the emitter, or collector to emitter etc. There is no potential difference at the collector alone so, it is a source voltage, Vcc (the c to c potential at the collector so what ever is there say +5V). Of course it is relative to something, so when measuring this you have to attach your voltmeter (or multimeter) to associated ground ((-) black) of the circuit and the other lead to the Vcc ((+) red). The same applies to the emitter (Vee) and base (Vbb). How the BJT is oriented in the circuit under test is relative to it's own orientation. PNP or NPN. P stands for positive and N stands for negative, so it is a relative junction or node (Some engineer types like to say node) relationship. I'm an engineer, but was a technician in the Navy so either one works for me.

Someone asked why the Vdd (drain) is positive yet the Vss (source) is negative. This is a matter of convention. Electrons flow not the atom (to much mass), so negative (electron charge = (-)) to positive (+) flow from the source (-) to the drain (+). So some metals have a more negatively charged molecule and others a less negatively charged molecule. Ask any physicist why there would be a huge ground plane. The electrons have to come from somewhere. Electron flow is from negative to positive always, always, always. Did I say always, well it's always.

Remember your electron valence shells around the atom from your basic electricity classes. Any physics II (or above) or chemistry student would know these facts too and best not disagree. If they do they are refering to charge flow.

Convention - Two thoughts here. Electron flow and hole or charge flow. That's it. Converse to electron flow is "charge" flow. Charge flow is from the positive voltage source to the negative voltage source. So if you have Vcc (+5 volts) and ground (0 volts) conventional flow states that the charge flow will be occurring in the opposing direction of the electron flow. It starts getting a little crazy after this, so we'll keep it simple right now.

Imagine an electron going in one direction and the charge in the other (a potential difference causing a reaction).

This stuff doesn't take months to write about (10 minutes tops). It's extremely simple. Other phenomena and effects can to a few hours to write out, but not this stuff.

• 
  BJT - Bijunctional Transistor (two diodes split at similar juctions - PNP and NPN).

• 
  FET - Field Effect Transistor (Has a base that use an electric field to control the conductivity of a charge carrier on semiconductor material: E-H field effects on substraight).

 

[kuiy11]

Vcc is Voltage Collector Collector
Vdd is Voltage Drain Drain
Vss is Voltage Source Source
Vce is Voltage Collector Emitter
Vbe is Voltage Base Emitter
Vec is Voltage Emitter Collecter

(You better write this correctly when designing or analyzing your circuits)

(I'm not going to talk about tubes)

Why the initial duplication (Vcc; the cc)? It accommodates the naming of Voltage "potential" of the Collector, or the emitter, or collector to emitter etc. There is no potential difference at the collector alone so, it is a source voltage, Vcc (the c to c potential at the collector so what ever is there say +5V). Of course it is relative to something, so when measuring this you have to attach your voltmeter (or multimeter) to associated ground ((-) black) of the circuit and the other lead to the Vcc ((+) red). The same applies to the emitter (Vee) and base (Vbb). How the BJT is oriented in the circuit under test is relative to it's own orientation. PNP or NPN. P stands for positive and N stands for negative, so it is a relative junction or node (Some engineer types like to say node) relationship. I'm an engineer, but was a technician in the Navy so either one works for me.

Someone asked why the Vdd (drain) is positive yet the Vss (source) is negative. This is a matter of convention. Electrons flow not the atom (to much mass), so negative (electron charge = (-)) to positive (+) flow from the source (-) to the drain (+). So some metals have a more negatively charged molecule and others a less negatively charged molecule. Ask any physicist why there would be a huge ground plane. The electrons have to come from somewhere. Electron flow is from negative to positive always, always, always. Did I say always, well it's always.

Remember your electron valence shells around the atom from your basic electricity classes. Any physics II (or above) or chemistry student would know these facts too and best not disagree. If they do they are refering to charge flow.

Convention - Two thoughts here. Electron flow and hole or charge flow. That's it. Converse to electron flow is "charge" flow. Charge flow is from the positive voltage source to the negative voltage source. So if you have Vcc (+5 volts) and ground (0 volts) conventional flow states that the charge flow will be occurring in the opposing direction of the electron flow. It starts getting a little crazy after this, so we'll keep it simple right now.

Imagine an electron going in one direction and the charge in the other (a potential difference causing a reaction).

This stuff doesn't take months to write about (10 minutes tops). It's extremely simple. Other phenomena and effects can to a few hours to write out, but not this stuff.

BJT - Bijunctional Transistor (two diodes split at similar juctions - PNP and NPN).
FET - Field Effect Transistor (Has a base that use an electric field to control the conductivity of a charge carrier on semiconductor material: E-H field effects on substraight).

 

[kuiy11]

what do Vcc, Vdd, and Vss mean? When is the appropriate time to use each?

thanks

david

Vcc is Voltage Collector Collector
Vdd is Voltage Drain Drain
Vss is Voltage Source Source
Vce is Voltage Collector Emitter
Vbe is Voltage Base Emitter
Vec is Voltage Emitter Collecter

(You better write this correctly when designing or analyzing your circuits)

(I'm not going to talk about tubes)

Why the initial duplication (Vcc; the cc)? It accommodates the naming of Voltage "potential" of the Collector, or the emitter, or collector to emitter etc. There is no potential difference at the collector alone so, it is a source voltage, Vcc (the c to c potential at the collector so what ever is there say +5V). Of course it is relative to something, so when measuring this you have to attach your voltmeter (or multimeter) to associated ground ((-) black) of the circuit and the other lead to the Vcc ((+) red). The same applies to the emitter (Vee) and base (Vbb). How the BJT is oriented in the circuit under test is relative to it's own orientation. PNP or NPN. P stands for positive and N stands for negative, so it is a relative junction or node (Some engineer types like to say node) relationship. I'm an engineer, but was a technician in the Navy so either one works for me.

Someone asked why the Vdd (drain) is positive yet the Vss (source) is negative. This is a matter of convention. Electrons flow not the atom (to much mass), so negative (electron charge = (-)) to positive (+) flow from the source (-) to the drain (+). So some metals have a more negatively charged molecule and others a less negatively charged molecule. Ask any physicist why there would be a huge ground plane. The electrons have to come from somewhere. Electron flow is from negative to positive always, always, always. Did I say always, well it's always.

Remember your electron valence shells around the atom from your basic electricity classes. Any physics II (or above) or chemistry student would know these facts too and best not disagree. If they do they are refering to charge flow.

Convention - Two thoughts here. Electron flow and hole or charge flow. That's it. Converse to electron flow is "charge" flow. Charge flow is from the positive voltage source to the negative voltage source. So if you have Vcc (+5 volts) and ground (0 volts) conventional flow states that the charge flow will be occurring in the opposing direction of the electron flow. It starts getting a little crazy after this, so we'll keep it simple right now.

Imagine an electron going in one direction and the charge in the other (a potential difference causing a reaction).

This stuff doesn't take months to write about (10 minutes tops). It's extremely simple. Other phenomena and effects can to a few hours to write out, but not this stuff.

BJT - Bijunctional Transistor (two diodes split at similar juctions - PNP and NPN).
FET - Field Effect Transistor (Has a base that use an electric field to control the conductivity of a charge carrier on semiconductor material: E-H field effects on substraight).