Considering transients in electric circuits, not to mention the fact that such phenomena are quite natural and to some extent predictable.Moreover, each person faces with their manifestation in your everyday life.For example, included in the network of the heating element (electric heater, oil heater), the temperature does not rise indefinitely, and to a certain value that depends on several factors such as ambient temperature, humidity level, the characteristics of the wire and so on. Accordingly, the cooling occursto a certain steady-state value, and not to absolute zero.In other words, all physical phenomena can be conditionally divided into transient and steady.The first is a change between the initial and final install.
What is transients in electrical circuits?When analyzing any circuit should be considered two possible modes: steady and transient.The first is characterized by repeated per unit of time the instantaneous values of an alternating voltage and current on all parts of the circuit.Transients in electrical circuits easier to understand when such changes are terminated, then we can talk about the occurrence of the steady state.The investigation following: a condition in which no changes can theoretically continue indefinitely.
transients in linear electric circuits are familiar to all.Certainly, in each case, after clicking the home switch the lamp burns out or even flew on the shards of glass bulb itself.Moreover, it can happen as a budgetary lamps and with expensive brand.In this "guilty" transients in electric circuits.In this case, the click of the switch caused the changes, initiated the transition process called switching (ie switching).In fact, the reasons may be different: change the power supply parameters, such as a short circuit, external influences (magnetic field, temperature) and so forth. The direct payment per unit of time-varying voltage and current is possible through the development of differential equations and calculate integrals.In the formulas, the number of derivative depends directly on the elements of the chain.
Since usually the duration of the transition process is not even counted in seconds and hundredths and thousandths of a second, it is sometimes a question of whether the calculations.Indeed, what could happen in such a short time?Alas, this is so only partially, and experience shows that quite a lot.For example, the power contacts are always designed for much higher current than the nominal.In addition, contacts are often closed arcing chambers (bars).This is due to the fact that at the time of switching (on / open circuit), the current is increased tenfold, and to eliminate the possible effects of these decisions apply.
consider transients rc circuits.For example, take the circuit comprising the power source, a pair of resistors (R1 and R2), a capacitor (C) and a voltmeter (V), connected in parallel.If your condenser has a capacity of tens of microfarads and a resistance R1 and R2 - a couple of hundred kilohms, respectively, when you turn on the source of the voltmeter needle is not immediately point to the actual voltage and gradually deviates from zero.This transient is caused by the accumulation of charge in the container.Accordingly, steady state comes at a time when consumption stops reactive component.
