25-08-2012, 12:48 PM
Power Diode Products
Definition of Power Diode Products.doc (Size: 29 KB / Downloads: 34)
DC or direct current – Since electricity can flow in either of two directions through a wire, we name the types of electricity by the way it flows. If it flows in only one direction it is called direct current. It is deemed positive in one direction and negative in the other. This is the type of voltage that is stored in battery.
AC or alternating current – This type of electricity flows in the shape of a sine wave, changing from one direction (positive) for the first half of the sine wave, to the other direction (negative) for the second half of the wave. It alternates from positive to negative during one full cycle, so it is called alternating current. This is the type of voltage that is supplied by the power company and is available in wall sockets.
There are two components of electricity that are easily measured; voltage and current. Voltage is measured in volts and is the electrical potential difference between two points in a circuit. If we use the comparison of water flowing through a pipe, the voltage would be the same as the water pressure. Current is the amount of electrons flowing past a point in a designated time, and is measured in amperes. To use the same analogy, current is the same as the volume of water flowing through the pipe.
Please note that the terms rectifier and diode are used synonymously. Since most electronic circuits use DC voltage, but power companies supply AC voltage, the first part of the circuit in almost every piece of electronics is a device called a rectifier. Its purpose is to change AC voltage into DC voltage. Rectifiers do this by only allowing current to flow in one direction, so they block any current trying to flow the other way.
Standard Rectifiers – This is the basic standard speed rectifier that General Semiconductor delivers to the world in prodigious volumes. The “Superectifier” line of rectifiers has been the benchmark of rectifier reliability for over twenty-five years. With a non-soldered, all-brazed construction the Superectifier is the choice for critical automotive “under hood” applications which are regarded as the most difficult and environmentally strenuous applications anywhere. The superectifier is available in leaded (through hole) and surface mount packages.
Bridge Rectifiers are essential for any electronic equipment which requires full wave rectification of an AC power source. The bridge rectifier is comprised of four separate rectifier components configured into a “bridge” arrangement in a single package. The bridge rectifier converts alternating current (AC) into direct current (DC). General Semiconductor manufactures a complete line of bridge rectifiers which meets the power and case style requirements of most electronic equipment.
Schottky Rectifiers – Schottky rectifiers are a specific style of diode designed for extremely fast switching times, often less than 10 nano seconds and low forward voltage drop. These characteristics result in greater efficiency making the Schottky rectifier a primary component in Switch Mode Power Supplies (SMPS). The end products these power supplies appear in are often desktop and mainframe computers.
Fast Efficient Rectifiers (FER) – These rectifiers are a natural extension of the Schottky product line. These are extremely fast, though not as fast as Schottky and are used in similar applications to their Schottky cousins. The advantage the FER products have is the ability to operate at higher voltages. Voltage range limitations are the primary restriction designers must be aware of when using Schottky devices. On the down side, the FER type of rectifier is not quite as fast or low loss as the Schottky.
Transient Voltage Suppressors (TVS) – This is a specialized form of rectifier. It is specifically designed to absorb energy and “clamp” voltage “spikes” or surges. These diodes are designed specifically to protect other, more delicate electronic components from electrical overstress. Based on controlled avalanche technology, these voltage clamping devices utilize a specific soft solder construction. This physical design enables these avalanche diodes to absorb large amounts of energy for short durations of time without sustaining damage. With sub-nanosecond turn-on times, no wear-out mechanism and excellent clamping characteristics, General Semiconductor’s TVS is the preferable option for transient suppression needs.