switching circuit voltage
switching circuit is also called variable voltage power switches.Feature use thyristors in this role is that they dissipate power is low, since during operation, they are either closed or, when opened, the voltage applied to them is small.Typically, in such switching circuits are used SCRs, i.e. SCRs.In this case, the drive current is supplied to the control electrode, respectively SCR.Another way to organize such a scheme is the use of a trigger diode, ie dynistor.The basis for the work of such a device is unlocked when the diode voltage value applied pulse above a gate.
When designing these schemes use the opportunity to change its state of the thyristor according to the applied voltage.The instruments built by this group schemes, are important only two para
meters: time unlocking and unlocking voltage.The first parameter is especially important in power circuits, because they unlocking occurs during energization of the thyristor.After some time, the voltage is reduced, and the current in the thyristor increases.Thus it dissipated fairly large capacity.
switching circuit DC voltage or
thyristors usually do not use in circuits with direct current, however, the fact that many of the thyristors have a large enough power is attractive for application in DC voltage or current.For this opportunity come up with some clever way to build circuits.For the purpose of switching DC Lockable thyristors used.These devices for some time interrupt current flow through.One such scheme is the scheme with two parallel thyristors.In this case, the pulse current through one of the thyristors are always twice through a second current pulse, which provides current commutation.
different experimental schemes
to experimental schemes, which use thyristors, are those that use the properties of the SCR transients, as well as areas of negative resistance.The fact that the current-voltage characteristics of the thyristor has a plot, in which the current decreases with increasing voltage across it, that is, section with negative resistance.This allows the use of a thyristor as an element with negative resistance, setting the operating point on the branch of the current-voltage characteristics, having a negative downturn.