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A Zener diode is a special type of diode designed to reliably allow current to flow "backwards" (inverted polarity) when a certain set reverse voltage, known as the Zener voltage, is reached. Zener diodes are manufactured with a great variety of Zener voltages and some are even variable.
In the Zener diode, the concept of PIV is not applicable. A Zener diode contains a heavily doped p–n junction allowing electrons to tunnel from the valence band of the p-type material to the conduction band of the n-type material, such that the reverse voltage is "clamped" to a known value (called the Zener voltage), and avalanche does not ...
Electrically, these devices resemble Zener diodes, with the following major differences: They rely on gas ionization, rather than Zener breakdown; The unregulated supply voltage must be 15–20% above the nominal output voltage to ensure that the discharge starts; The output can be higher than nominal if the current through the tube is too low.
Light-emitting diodes (LEDs) produce light (or infrared radiation) by the recombination of electrons and electron holes in a semiconductor, a process called "electroluminescence". The wavelength of the light produced depends on the energy band gap of the semiconductors used.
The DO-35 (also known as DO-204-AH or SOD27) is a semiconductor package used to encapsulate signal diodes (i.e., diodes meant to handle small amounts of current and voltage). [ 10 ] [ 13 ] [ 2 ] It is often used to package small signal, low power diodes such as 1N4148 (a 100 V, 300 mA silicon diode.)
Three 1N4148 diodes in glass DO-35 axial package. The black band on the right is the cathode side. Diode schematic symbol vs cathode marking on the package. The 1N4148 is a standard silicon switching signal diode. It is one of the most popular and long-lived switching diodes because of its dependable specifications and low cost.
Tris(8-hydroxyquinolinato)aluminium is the chemical compound with the formula Al(C 9 H 6 NO) 3. Widely abbreviated Alq 3 , it is a coordination complex wherein aluminium is bonded in a bidentate manner to the conjugate base of three 8-hydroxyquinoline ligands .
The aluminium complex, [3] is a common component of organic light-emitting diodes (OLEDs). Substituents on the quinoline ring affect the luminescence properties. [4] In its photo-induced excited-state, 8-hydroxyquinoline converts to zwitterionic isomers, in which the hydrogen atom is transferred from oxygen to nitrogen. [5]