# Electronics Basics: Vcc, ground, ...

> Learn why electronics uses so many names for the same pins: GND, Vss, 0V for the negative pole and Vcc, Vdd for the positive, split between TTL and CMOS.

Author: Flavio Copes | Published: 2020-12-13 | Canonical: https://flaviocopes.com/electronics-vcc-ground/

In all the projects and explanations I will use various terms to identify the same thing.

In particular I could mention `-`, `0V`, negative pole of the battery, ground, `GND` and `Vss`.

Those all mean the negative pole of the battery that is at 0V.

On the other side of the spectrum I mention `+`, `Vcc`, `Vdd` or positive pole.

This refers to the positive pole of the battery which exact value will be different depending on the battery or power source used: `9V`, `3.3V`, `5V`, and so on.

Why so many terms? Different families of electronic components adopted different acronyms:

- **TTL** (Transistor-Transistor Logic) components use `Vcc` and `GND`.
- **CMOS** (Complementary Metal-Oxide-Semiconductor) components use `Vdd` and `Vss`).