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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.
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:
These characteristics are also known as I–V curves, referring to the standard symbols for current and voltage. In electronic components with more than two terminals, such as vacuum tubes and transistors , the current–voltage relationship at one pair of terminals may depend on the current or voltage on a third terminal.
Shockley derives an equation for the voltage across a p-n junction in a long article published in 1949. [2] Later he gives a corresponding equation for current as a function of voltage under additional assumptions, which is the equation we call the Shockley ideal diode equation. [3]
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.
Firstly, consider a mathematically idealized diode. In such an ideal diode, if the diode is reverse biased, the current flowing through it is zero. This ideal diode starts conducting at 0 V and for any positive voltage an infinite current flows and the diode acts like a short circuit. The I-V characteristics of an ideal diode are shown below:
scr in ac circuit ( light dimmer circuit ) In AC circuit, we don’t have the latch circuit due to the change of alternating current. By adjusting R2, we change the charging time to capacitor C, the time constant T = (R1 + R2)xC is called time delay angle or fired delay time which is the time to start firing SCR.
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 ...