Aloitusjännite

Aloitusjännite, often translated as ignition voltage or breakdown voltage, refers to the minimum voltage required to initiate a specific electrical phenomenon. In the context of gas discharge, it is the voltage necessary to cause a sustained electrical discharge through a gas. When a voltage is applied across two electrodes in a gas, a small current may flow. As the voltage increases, more electrons are freed, and these electrons gain energy from the electric field. These energetic electrons collide with gas atoms, ionizing them and freeing more electrons. This process, known as an avalanche effect, leads to a rapid increase in current and the formation of a plasma, resulting in a visible discharge like a spark or glow. The precise value of the aloitusjännite depends on factors such as the type of gas, its pressure, the distance between the electrodes, and the electrode geometry.

The concept of aloitusjännite is crucial in various applications. In fluorescent lighting, it's the voltage needed to start the discharge that excites the gas and produces UV radiation, which then interacts with the phosphor coating. In spark plugs for internal combustion engines, it's the voltage that overcomes the resistance of the air-fuel mixture to create a spark and ignite it. In lightning, it's the immense voltage built up in clouds that eventually causes a discharge to the ground. Understanding and controlling aloitusjännite is essential for the reliable and efficient operation of these technologies. Conversely, exceeding the breakdown voltage of insulating materials can lead to electrical failures.