Power Abreviations

[windozeuser]

Whats Vss, Vdd, and Vin mean by convention?

 

[Someone Electro]

Vss positive suply
Vdd negative suply
Vin some kind of input voltage.

Vss and Vdd is mostly used by digital circuits.

 

[Nigel Goodwin]

Vss and Vdd is mostly used by digital circuits.

Actually it's usually CMOS circuits, as Vss refers to source voltage and Vdd refers to drain voltage.

 

[windozeuser]

In my BASIC stamp Manual It saids Vdd is Positive and Vss is Negative(drain to ground)

 

[Joel Rainville]

**broken link removed**

Why do most circuits I've seen have been using Vss for ground and Vcc, Vdd for the positive supply?

 

[Nigel Goodwin]

http://www.maxim-ic.com/glossary/index.cfm/Ac/V/ID/943/Tm/VDD/ln/en

Why do most circuits I've seen have been using Vss for ground and Vcc, Vdd for the positive supply?

Because the DRAIN of the FET's goto to positive (Vdd), the collector of a bipolar IC goto positive (Vcc), and the SOURCE of the FET goes to ground (Vss).

These obviously apply to NPN and N channel devices, but it's common practice for IC's, and used regardless of polarity (a chip will almost certainly have BOTH polarity devices internally anyway!).