What is SCR bridge?
Silicon Controlled Rectifiers – SCRs The function of the SCR bridge is to control the amount of voltage applied to the motor. The SCR, sili- con controlled rectifier, is similar to standard rectifiers in that it will allow current to flow in one direction while blocking current in the reverse direction.
What is a bridge rectifier circuit?
Bridge Rectifiers are circuits that convert alternating current (AC) into direct current (DC) using diodes arranged in the bridge circuit configuration. Bridge rectifiers typically comprise of four or more diodes. The output wave generated is of the same polarity irrespective of the polarity at the input.
What is SCR and its working?
The electric name of Silicon controlled or the semiconductor controlled rectifier (SCR) is Thyristor. SCRs are responsible for conducting the flow of current in a single direction. Hence it is also a unidirectional device. It consists of three junctions in it. These are the devices that operate based on the currents.
What is SCR full wave rectifier?
For full-wave rectification two SCRs are connected across the centre taped secondary, as shown in figure-a. One SCR conducts during the positive half cycle and the other during the negative half cycle and thus unidirectional current flows in the load circuit.
How does the SCR differ from an ordinary rectifier?
Explanation: Only diodes are used in ordinary rectifier. The SCR and diodes are used in controlled rectifier. The freewheeling diode is necessary in controlled rectifier.
What is rectifier circuit?
A rectifier is an electrical device that converts alternating current (AC), which periodically reverses direction, to direct current (DC), which flows in only one direction. The process is known as rectification, since it “straightens” the direction of current.
Where are SCR used?
SCRs are mainly used in devices where the control of high power, possibly at high voltage, is needed. The ability to switch large currents on and off makes the SCR suitable for use in medium to high-voltage AC power control applications, such as lamp dimming, regulators and motor control.
How can an SCR be turned off?
SCRs may be turned off by anode current falling below the holding current value (low-current dropout) or by “reverse-firing” the gate (applying a negative voltage to the gate). Reverse-firing is only sometimes effective and always involves high gate current.
Why SCR is known as latch device?
Once the SCR starts conducting, no more gate voltage is required to maintain it in the ON state. The minimum current necessary to maintain the SCR in the ON state on removal of the gate voltage is called the latching current.