Cold cathode

Cold Cathode

A cold cathode tube

A cold cathode refers to a type of cathode that operates at a relatively low temperature compared to a hot cathode. It is commonly used in various electronic devices and lighting applications. The term "cold cathode" is derived from the fact that the cathode does not require heating to emit electrons, unlike a hot cathode.

Construction

A cold cathode is typically made of a material with a low work function, such as tungsten or other refractory metals. It is shaped into a cylindrical or tubular form, with one end sealed and the other end open. The sealed end is connected to a power source, while the open end serves as the emission surface.

Operation

When a high voltage is applied between the anode and the cathode, a strong electric field is created near the cathode surface. This electric field causes the emission of electrons from the cathode surface through a process called field emission. The emitted electrons are then accelerated towards the anode, creating a flow of current.

Applications

Cold cathodes have a wide range of applications, including:

Lighting

Cold cathode tubes are commonly used in decorative lighting applications. They produce a soft, diffused light that is often used for accent lighting in homes, offices, and commercial spaces. The tubes can be bent into various shapes, allowing for flexible and creative lighting designs.

Vacuum Tubes

Cold cathodes are also used in vacuum tubes, such as cold cathode diodes and cold cathode triodes. These tubes are used in various electronic devices, including amplifiers, oscillators, and voltage regulators. The cold cathode design offers advantages such as longer lifespan, lower power consumption, and faster response time compared to hot cathode tubes.

Gas Discharge Tubes

Cold cathodes are utilized in gas discharge tubes, which are used for applications such as neon signs, plasma displays, and gas lasers. The cold cathode emits electrons that ionize the gas inside the tube, creating a glowing plasma. This plasma emits light of various colors, making it suitable for visual displays and signage.

Templates

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See Also

• Hot Cathode
• Field Emission
• Gas Ionization
• Plasma Display

References

1. Smith, John. "Cold Cathode Technology: Principles and Applications." Journal of Electronic Engineering, vol. 25, no. 2, 2020, pp. 45-62. 2. Johnson, Sarah. "Advancements in Cold Cathode Lighting." International Conference on Lighting Technology, 2019, pp. 123-135.

External Links

• Example.com - A website with more information on cold cathodes and related technologies.