# Where do these grounding wires go? [duplicate]

In the following schematic the two Vss pins where are supposed to be the grounding pins don't connect to anything. Does this mean that the circuit is self-grounding (if that's even a thing)?

I'm planning on attaching this to a breadboard but I'm not sure how to power it since I don't have a direct connection to the TSL1402 ship and have to go through the accessible pins.

Here is the schematic:

• That triangle is a typical symbol for ground. Notice that there are others like it. They should all be connected together. The actual supply ground connection is made on J1. This is where you connect your power supply. May 31, 2016 at 16:59
• Short answer: Connect all of the ground symbols together (I see 3 others in your circuit). May 31, 2016 at 17:00
• Also, this answer: electronics.stackexchange.com/questions/57923/… May 31, 2016 at 17:02
• The term and symbol "ground" is confusing and have >1 meanings. In case of electronics, usually the ground symbol indicate NEGATIVE (negative input to the circuit). Though sometimes a positive ground occur (I've read it somewhere in Web, but yet never seen a positive ground in circuit diagram), the negative end of the electrolytic capacitors (its cathode), (such as C3 on this diagram) indicates it might be a negative ground.
– user107801
Jul 1, 2016 at 18:37
• On that IC, pin 6 and 7 tied together, with conductor, means, these pins are on same voltage (here the voltage supplied by negative ground). since a good-conductor (metals) have very low resistivity, wires and connectors considered as zero-Ohms (though they're not), all the portions connected with continuous conductor, could be considered as a single point having single voltage.
– user107801
Jul 1, 2016 at 18:48

simulate this circuit – Schematic created using CircuitLab

Figure 1. Various "ground" symbols.

In most circuits there is a common rail which is used as a reference for all other points in the circuit. One of the most common examples is the automobile / car electrical systems which use the chassis as the return path to the battery negative. Most circuits use the power supply negative as the common rail but many don't (and cars used to use positive earth many years ago).

Using a symbol for ground makes schematics more readable as it eliminates many wires.

• The signal ground symbol is commonly used in electronic schematics.
• The 'earth' symbol is used for a real earth connection on an electrical power distribution diagram but is often seen in auto electrical schematics and electronics circuits to signify a connection to electrical ground.
• The 'chassis' symbol will appear in electronic schematics to indicate connection to the metal frame or chassis of the device.

In an isolated system - your mobile phone, for example - the "ground" is isolated from everything else until you plug it into a charger.

Does this mean that the circuit is self-grounding?

No. It just means a common "ground" or reference rail.

The symbol you highlighted is the ground symbol. On a breadboard, all these symbols are attach to each other. This is the reference for the ground of your D.C. power supply. So for any voltage measurement, you take this point as the reference so the 5V point will be 5 volts higher than this reference.

The symbol with the three short horizontal lines (see below) is an indication of a GND connection. It is normally understood that all symbols like this on a schematic are tied (a.k.a. connected) together.

You will note that there are also GND connections at the connectors J1 and J3. One of these can be the place you can connect in the GND from your breadboard.

Since you claim you don't have access to the chip I assume the displayed schematic is from some kind of module?

The ground symbol (3 horizontal bars stacked on top of each other in a triangle shape) is a graphical tool to connect all ground lines/pins with one another without drawing traces all over the schematic. So every time you see this ground symbol it is logically connected with every other ground symbol.

To connect the ground of your power supply to this schematic, use the one pin of J1 or the one pin of J3 that is connected to the same ground symbol.

• The statement "So every time you see this ground symbol it is logically connected with every other ground symbol" very much helpful to me.
– user107801
Jun 1, 2016 at 10:02