# Naming for battery voltage supplies

#### Dritech

Joined Sep 21, 2011
873
Hi all,

When having a circuit powered by battery, which are the best abbreviations to use for the supply lines ? Should I use the GND symbol when a circuit is powered by a battery (as shown below)?

In the example below, for the output terminals of the battery, should I used Vdd for the 6V and Vss for the 0V instead of Vs and GND?
For the output of the switch (which can toggle between 5V and 3.3V) is Vreg a good abbreviation to use?

#### SamR

Joined Mar 19, 2019
3,425
Vs and Gnd/GND are fine for batteries, Vcc and Vdd came from transistors to indicate Vcommon and Vdrain. Even POS/+ & NEG/-. YMMV

Last edited:

#### ericgibbs

Joined Jan 29, 2010
12,974
hi Dri,
When using just the 'V' letter, I prefer to prefix the letter with the '+' or '-' symbol, it makes the polarity clear to the reader.
Also for battery I use +Vbty or -Vbty, so it is obvious that it powered from a battery source.
eg: +12Vbty..

Some use Vss or Vcc, Vdd or Vee , ie: transistor's, fet's

Gnd or 0V, usually refers to the measurement reference Node, I only use Earth for an actual connection to physical Earth

On your switch diagram I would use Vin, Vo1, Vo2.

E

#### Audioguru again

Joined Oct 21, 2019
3,208
Your voltage regulator has no part number. A 7805 or an LM317 needs a minimum input voltage of 7V but your battery is only 6V when new and drops to 4V during its life. For a 3.3V output the input must be 5.3V or more.
"Low Dropout" regulators work with input voltages near the output voltage.

#### dl324

Joined Mar 30, 2015
12,873
In the example below, for the output terminals of the battery, should I used Vdd for the 6V and Vss for the 0V instead of Vs and GND?
You shouldn't use Vdd or Vss unless you're using CMOS, where those names are commonly used for power and ground, respectively.
For the output of the switch (which can toggle between 5V and 3.3V) is Vreg a good abbreviation to use?
No. You have two voltage regulators and Vreg would be ambiguous.

Unless your 5V regulator is an LDO, 6V isn't high enough for it to regulate.

#### sparky 1

Joined Nov 3, 2018
544
Some will read this and not be happy, to others it reads ok.
There is a decision when to throw away a AA battery for example the battery drops to 1.1V
then 6 each AA make the minimum Vbat total of 6.6Vdc. A 5V LDO and 3.3 V regulator would use the 5V LDO voltage as the limiting factor. I read your schematic as a missing batteries error. Others would refer to the actual board and say yep it's a 5V step up converter not a standard 5V regulator what a lazy. Lots of different words and abbreviations and some will use something different just to be different. So it is what makes sense to you and and those who will need to refer to a pictorial schematic. It is a good topic about using standard abbreviation or naming.

Last edited: