In the automotive context, an emergency starting power supply refers to a device that is used to jump-start a vehicle with a dead or weak battery. 

This device is sometimes called a "jump starter" or "booster pack." It provides a temporary power source to help start the vehicle's engine when the vehicle's own battery does not have sufficient charge to do so. 

Features and functions:

1.Portable Device: An emergency starting power supply is a portable device that typically includes a rechargeable battery and jumper cables. Some modern versions may even come with features like USB ports for charging devices and built-in air compressors for inflating tires.

2.Connection: To jump-start a vehicle, you connect the jump starter to the dead battery. The positive (red) cable is connected to the positive terminal of the dead battery, and the negative (black) cable is connected to a metal, unpainted part of the vehicle's chassis to ground it.

3.Start the Engine: Once the connections are made, you turn on the jump starter and attempt to start the vehicle. The jump starter provides the necessary power to turn the engine over, allowing it to start even if the vehicle's battery is weak or dead.

4.Safety: It's essential to follow safety precautions when jump-starting a vehicle to avoid electrical issues or accidents. Ensure the jump starter is used correctly, and the connections are secure.

Emergency starting power supplies in the automotive context are valuable tools for getting your vehicle back on the road when you're faced with a dead battery. 

They are especially handy in situations where you may not have access to another vehicle to use traditional jumper cables.