# What is the meaning of “ground” and “-V” in a simple push-pull circuit?

In this simple "push-pull" circuit, there are +V, -V and ground connections. up until now, i always considered ground to be the minus side of the battery. but that is also the way i understand -V, so i don't see how current would flow through the PNP transistor from ground to the -V

If i am using this circuit to drive a simple DC motor forwards(push) and backwards(pull) with a battery what would the -V and ground connections mean ?

When using a 'split rail' like this, ground will be the mid terminal of the battery or power supply. So if you had a +12v and a -12v supply, that would need two 12v batteries, connected in series, with their mid point taken to be ground.

This split rail connection allows you to generate both positive and negative voltages into the load. Your motor would connect between ground and $V_E$. This would allow it to be driven in either direction.

If you wish, you needn't label "ground" or "V+" or "V-" at all. Or put them where you wish. Your schematic is re-drawn with none labeled:

simulate this circuit – Schematic created using CircuitLab
The usual place to put "ground" is where Vin meets the junction of the two DC supplies, in this dual-supply circuit.

All ground means is.. "This is my reference point".

Or, to put it another way..

"When taking voltage measurements in this circuit.. connect the voltmeter or scope black lead here."

You can make the "ground" anything you want... even the positive terminal of the battery if it helps make the function of the circuit more understandable.