What is a device that allows electric current to pass through it in one direction only, used for converting AC to DC?

Question

What device, a tool for studying astronomical phenomena, uses the fact that when a material is heated to incandescence it emits light that is characteristic of the atomic makeup of the material?

Answer 1

Thanks for the query.

The answer is - A Diode. A diode is an electrical device which allows flow of current in one direction with greater ease than the other. The most common kind of diode in modern circuits is the semi conductor diode.

Source - https://en.wikipedia.org/wiki/Diode
http://www.allaboutcircuits.com/textbook/semiconductors/chpt-3/introduction-to-diodes-and-rectifiers/

Answer 2

In addition to the Diode (used in micro-circuits also known as "chips") another term for converting AC to DC (on a larger scale) is known as a Rectifier.

Many applications of rectifiers, such as power supplies for radio, television and computer equipment, require a steady constant DC current.

Also, in these applications, the output of the rectifier is smoothed by an electronic filter (usually a capacitor) to produce a steady current.