Vcc vs Vss

B

banh

New Member

• Aug 23, 2004

• #1

I've seen some schematics and see some pins using Vcc, while others Vss. What's the difference between two?

 

samcheetah

New Member

• Aug 23, 2004

• #2

its just different names for different transistor technologies.

Vcc is the conventional name for the collector supply of a bipolar transistor and Vss is the conventional name for the source supply of an field effect transistor.

 

B

banh

New Member

• Aug 24, 2004

• #3

so all 5 V rite?

 

Styx

Active Member

• Aug 24, 2004

• #4

if that is what the maximum voltage of the chip/part is, then yes

 

J

JohnBrown

New Member

• Aug 24, 2004

• #5

I think you'll find that Vss is usually 0V, Vdd is the 5V(3.3V/3.0V)

 

Nigel Goodwin

Super Moderator

Most Helpful Member

• Aug 24, 2004

• #6

Personally I really hate these silly labels, and I never use them - I label +5V, GND (or 0V) and -5V, these are much more sensible than Vcc, Vdd and Vss.

 

samcheetah

New Member

• Aug 24, 2004

• #7

i agree with u Nigel but most of the things that are conventional are silly!!!

we are taught these things in college and we have to work with them everyday and thats why they never disappear. it looks like we will have to live with them!

 

S

Samad Khan

New Member

• Jul 8, 2010

• #8

What is diffrence between Vss and Vs

In L298 motor contrl IC there r pins with Vs Supply Voltage and Vss Logic Supply Voltage so can u tell me what is differnce between thm.....

 

Vizier87

Active Member

• Jul 8, 2010

• #9

Salam Samad, welcome to the forum.
it'll be very advisable to open a new thread for your question but since you're new here it's okay.

Vs is for the motor power up, a range of 2.5-46V
Vss is the logic circuitry supply. Only 4.5-5V is needed, which can be derived from an LM7805.

 

3v0

Coop Build Coordinator

Forum Supporter

• Jul 8, 2010

• #10

I am so used to seeing Vss as ground that the use of it for a "logic supply voltage" seems odd.

 

Vizier87

Active Member

• Jul 8, 2010

• #11

yeah, me too! But it is so on the datasheet. This Vss-Vcc-Vdd business really riles me up.

 

S

Samad Khan

New Member

• Jul 8, 2010

• #12

So now wht to do..
how will we find the diffrence

 

D

Dx3

New Member

• Jul 8, 2010

• #13

Read the labels.

Somewhere, every Vwhatever can be traced to a power supply.

I hope.

 

Vizier87

Active Member

• Jul 9, 2010

• #14

Samad, I've answered the question in the first page of this thread.

 

S

Samad Khan

New Member

• Jul 9, 2010

• #15

Wsalam Vizier 87.

Thank you So much for your answer it reduced my tension..
kindly tell me ur Email address as i may need ur guidance.
u can contact me at mr.samadkhan@gmail.com
thank u soo much.