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A simple SCR circuit with a resistive load. A simple SCR circuit can be illustrated using an AC voltage source connected to a SCR with a resistive load. Without an applied current pulse to the gate of the SCR, the SCR is left in its forward blocking state. This makes the start of conduction of the SCR controllable.
Tunnel diodes and Gunn diodes are examples of components that have negative resistance. Hysteresis vs single-valued: Devices which have hysteresis; that is, in which the current–voltage relation depends not only on the present applied input but also on the past history of inputs, have I–V curves consisting of families of closed loops. Each ...
The Villard circuit, conceived by Paul Ulrich Villard, [p 1] consists simply of a capacitor and a diode. While it has the great benefit of simplicity, its output has very poor ripple characteristics. Essentially, the circuit is a diode clamp circuit. The capacitor is charged on the negative half cycles to the peak AC voltage (V pk). The output ...
The characteristics and components of ripple depend on its source: there is single-phase half- and full-wave rectification, and three-phase half- and full-wave rectification. Rectification can be controlled (uses Silicon Controlled Rectifiers (SCRs)) or uncontrolled (uses diodes). There is in addition, active rectification which uses transistors.
Their characteristics and limitations are a key element in the design of power electronics systems. Formerly, the mercury arc valve, the high-vacuum and gas-filled diode thermionic rectifiers, and triggered devices such as the thyratron and ignitron were widely used in power electronics. As the ratings of solid-state devices improved in both ...
low SCR: in case of a short circuit, the current is proportional to SCR, therefore generators with low SCR require less protection and thus are cheaper; low SCR allows shorter air gap and lower excitation field, both decreasing the size (an cost) of the generator; with low SCR the amounts of iron and copper are reduced, lowering the cost; high SCR:
A resistor removed from a high voltage tube circuit shows damage from voltaic arcing on the resistive metal oxide layer. Resistors can fail open or short, alongside their value changing under environmental conditions and outside performance limits. Examples of resistor failures include: Manufacturing defects causing intermittent problems.
The VI characteristics of typical STATCOM. As a STATCOM's VSC operation is based on changing current flow to affect voltage, its voltage-current (VI) characteristics control how it operates. [23] The VI characteristic can be divided into two distinct parts: a slopped region between its inductive and capacitive maximums, and its maximum ...