Ignition techniques refer to methods used to initiate combustion in various applications, such as engines, furnaces, and fireworks. Common techniques include using a spark plug, which generates a spark to ignite fuel-air mixtures, or employing a pilot light, a small flame that ignites gas when needed. In addition to these, other methods like friction ignition and chemical ignition are also used. Friction ignition involves creating heat through friction, while chemical ignition relies on a reaction between substances to produce heat and light. Each technique is chosen based on the specific requirements of the application.