Transformers are devices based on the phenomenon of electromagnetic induction and is composed in its simplest form, two coils wound on a closed core of iron sweet or silicon iron. The coils or windings are called primary and secondary as applicable to the entry or leaving the system in question, respectively. There are also more winding transformers in this case, there may be a winding "third", less tension than the secondary.
Schematic representation transformer. Applying a
emf alternative in the primary winding, variations in intensity and direction of the alternating current create a magnetic field variable depending on the frequency current. Variable magnetic field originated by electromagnetic induction , the appearance of an electromotive force at the ends of the secondary winding.
The relationship between the induction electromotive force (Ep), applied to the primary winding and the induced electromotive force (S), obtained in the secondary is directly proportional to the number of turns of primary winding (Np) and secondary (Ns).
Types of transformers
three-phase transformer. Star-delta.
According
applications up transformer / voltage reducer
are used in the substations of the transmission power in order to reduce losses by Joule effect. Due to the resistance drivers should carry the high voltage electricity, being necessary to further reduce these tensions to suit the use.
isolation transformer provides galvanic isolation between the primary and secondary, so getting a signal power or "floating." Usually has a 1:1 ratio. It is mainly used as a protective measure, in teams that work directly with the voltage. Also for coupling signals from remote sensors in electromedical and where floating voltages are needed each other. Power Transformer
may have one or more secondary windings and provide the necessary voltages to operate the equipment. Sometimes fuses incorporate cutting its primary circuit when the transformer reaches an excessive temperature, preventing it from burning, with smoke and gases involved, and even a fire hazard. These fuses are not usually replaceable, so you have to replace the entire transformer.
pulse transformer is a special type of transformer with very fast response (low inductance) for operation at pulse.
online or flyback transformer
is a particular case pulse transformer. It is used in CRT TVs (CRT) to generate the high voltage and current to the horizontal deflection coils . Also usually provide other voltages for the tube (Focus, filament, etc.).
diode split transformer
is a type of transformer line that incorporates the diode rectifier to provide DC voltage directly to the tube MAT. Called diode divided because it is formed by several smaller diodes divided by the winding and connected in series so that each diode has to withstand only a relatively low reverse voltage. The output transformer goes directly to the anode of the tube without diode or tripler. Impedance transformer
This type of transformer is used to adjust antennas and transmission lines (network cards, phones ...) and was essential in tube amps to adapt the high impedance tubes down from the speakers. If the child is placed in an impedance of value Z, and call na Ns / Np, as Is =- Ip / n Es = Ep.n, the impedance seen from the primary will be Ep / Ip =-En / n ² Is = Z / n ². Thus, we have managed to transform an impedance value in another Z Z / n ². By placing the transformer in reverse, so we do is raise the impedance by a factor n ².
voltage stabilizer is a special type of transformer in which the core is saturated when the voltage on the primary exceeds its nominal value. Then, changes in the secondary voltage are limited. He had a work to protect computers from power fluctuations. This type of transformer has fallen into disuse with the development of electronic voltage regulators due to its size, weight
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