Re: VRD - ground symbol (electricity)

The symbol that you "drew" is the symbol for an "earth ground."  This means 
that anything connected to this ground will also have an electrical path to the 
earth, and will therefore be at earth potential.  In nearly all dc circuits, 
the "negative" side of the power supply is connected to the earth ground.  
Although this configuration is common, you should always check to see if you 
have a positive ground or negative ground system.  It is possible to have more 
than one kind of ground system in a circuit, which is why there are different 
symbols for various types of ground.

So, IF you have a properly grounded circuit, AND there is only one ground in 
use, AND that ground is a negative ground, THEN you can view the ground symbol 
and the negative (-) symbol as the same thing.

By the way, the ground establishes a reference point for the voltage.  When a 
something says, for example, +5V, this means that the voltage needs to be 5 
volts above the ground (ground = 0V for an earth ground).  When you connect the 
negative side of the power supply to the earth ground, you establish a 
potential difference (i.e., voltage difference) of 5V between the 
ground/negative and the positive side.