Using ground as a reference point for measuring voltages

[webplodder]

Hello. I have been reading about using some arbitrary point as ground in a circuit in order to measure voltages with respect to it but am still perplexed because the text I am reading does not seem to make clear why this is useful in electronics. Any help appreciated. Thank you.

[electric_guide]

Ground is only a connection point between all relevant components in the electronic circuit in order to make one reference point.

it is not really connected to the ground.

for example a battery with DC voltage (+ and -) connected to a voltage divider with resistors.

in order to measure the voltage on one resistor related to the battery you need to define a reference point.

you call the (-) tap of the battery a "ground" and measure all voltages related to this point (the + tap of the voltmeter connected to the measure point and the - tap connected to "ground" point)

another simple example is connecting to boards (to circuits together).

you must connect them with a reference point . you take the ground point of each circuit and connect them together.