What is a crystal radio?

Crystal radio receiver is the earliest form of invented radio and first began to be produced after the rectification feature of the crystal crystals discovered in 1874 by German inventor Karel Braun. Many crystal forms, such as mineral galena or lead sulfide, which served as a crystal component of early crystal radios, allows the electric current to go through only one direction. As a result, they are useful for converting signals of AC current (AC) radio waves to direct current (DC) signals so that sound transmissions can be separated from the wave of the radio carrier and listened. The principle of rectification crystals has led to a wide range of crystal radio receivers around the world, including their normal use in the First World War I. Because the batteries do not require the batteries and it was easy to build, as long as in the early 20th century stronger radio receivers developed.

The crystal set can only be created with four functional parts. Belongs to nO: Antenna, tuning coil, crystal and headphone detector. The antenna is used to capture all the surrounding radio waves present at the designated location and directs their performance into the crystal radio as an electric current. The tuning coil is the winding of the copper wire, which is used to tune most of the waves present, so that only the required is processed. This selected radio wave frequency is directed to the crystal detector, which separates the bearing radio wool from the sound signal that travels through the air. Because the audio signal is usually relatively weak in the absence of amplifier powered from the battery, the headphones are then used to listen to the crystal radio to maximize volume levels.

Since 2011, crystal radios have been still produced as the subject of school scientific experiments and electrical fans, but their low energy and limited ability to capture far from radio signals that were obsolete as commercial products. Modern components also made it easierbuild. This involves replacing the cat's receiver for a firm condition of the crystal diode. The original crystalline structure used a natural crystal, which was connected with a beard electrode of wire cats. The electrode had to move around the crystal until the location was found where the crystal grid structure would transfer the signal over the headphones.

Crystal diodes use the same principle of rectification as the cat's beard receiver, but do not require any manual settings for the transfer of radio signal as soon as it is tuned by a ladic coil. Several different types of semiconductor crystals were used to perform this role except Galena, including silicon carbide, iron pyrite and bornit-binite. Any material that has a semiconductor electrical properties instead of a real crystal on a crystal radio. This includes common objects such as copper American pennies that have gained a tainted, semiconductor oxidized surface with age, but the crystals themselves are the simplest MATerial with which he can work with creating a crystal radio and the most effective.