Power Supply Nomenclature

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原文链接：https://miscircuitos.com/what-are-the-meaning-of-vdd-vss-vcc-vee-and-gnd/

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文章解释了电子电路中常见的电源电压符号Vdd、Vss、Vcc和Vee的含义。Vdd通常代表正电压，如3.3V或更低，而Vss表示零伏。在BJT电路中，Vcc是集电极电压，Vee是发射极电压；在FET或MOSFET电路中，Vss是源极电压，Vdd是漏极电压。文章旨在澄清这些术语在不同类型的晶体管内部的应用。

What are the meaning of Vdd and Vss? Vcc and Vee?? GND? - Mis Circuitos

It has always been a bit intriguing and even confusing the nomenclature of these power voltages (Vdd and Vss) or (Vcc and Vee).

The following pictures are worth a thousand words…

VDD, VSS, Vcc and Vee in Cadence

schematic

Nowadays it is always used Vdd and Vss to refer to the positive and negative voltage respectively. Vdd normally was used to be 5V but nowadays is 3.3V or even lower 1.8V or 1.2V. Vss is referred to be zero volts.

But I was taught, in the high school and during my first years of electronics, that Vcc is the positive voltage (usually 5 volts) but when we get to some circuits we find pins Vdd, Vss and Vdd. Maybe many have not been intrigued by this but if you are reading this probably yes. So let’s continue:

What is the nomenclature?

This depends on the type of transistors that the electronic device has internally the microchip, circuit or microcontroller.

If internally formed by bipolar transistors (BJT), then the nomenclature is:
–Vcc for being the voltage applied to the Collector of the transistors
–Vee for being the voltage applied to the transistor Emitter leg

If internally built by Field Effect Transistors (FET, MOSFET), the nomenclature is:
–Vss for being the voltage applied to the transistor Source pin
–Vdd for being the voltage applied to the Drain of the transistors

So what is the polarity of each one?

Because NPN and NMOS transistors are used as a reference: