0
thyristor can be scr or triac
scr is strictly dc
a triac is back to back scr's with a common gate
two scr's back to back can be gated independently
scrs cost less than triacs
an scr can be combined with a full wave bridge to make an equivalent to a triac
but this gives an additional 1.5V forward voltage drop
Wiki User
∙ 11y ago
Add your answer:
Earn +20 pts
Why doesn't an SCR switch off once it turns on even after reducing gate potential?
A thyristor or silicon controlled rectifier (SCR), as they are sometimes known, consists of two transistors. A pulse on the gate turns on the second transistor which then turns on the first transistor in the combination. Turning on the first transistor enables anode current to flow and maintains a base current for the second transistor which keeps it on.See the Related link for an equivalent circuit for an SCR or thyristor.
How does a triac differ from SCR?
An SCR is a rectifier and can only conduct in one direction (half wave).A Triac can conduct in both directions (full wave).
What does a thyristor works as a circuit breaker?
A thyristor is a type of semi-conductor and is used in a circuit to control the application of electrical power to a load. They are often found as the switching element in light dimmers and can be used as control elements in power supplies (variable or regulated). Types of thyristors are diacs, triacs, sidacs and SCRs (silicon controlled rectifier).
Why does a SCR have negative resistance?
Whenever you measure resistance, the resistance itself cannot be negative!When an SCR (Semiconductor Controlled Rectifier) is not conducting, it has a high resistance between its anode and its cathode. When its gate is triggered and the SCR is conducting, it has a low resistance between its anode and its cathode.For more information about SCRs, see the answer to the Related Question (for which a link is shown below) and also the Related Link.
What is the basic function of the SCR's gate electrode?
The SCR's gate electrode is used to turn the SCR on, i.e. fire it.
What is the difference between a transistor and scr?
SCR or Silicon Controlled Rectifiers are Bipolar junctions Transistor ( Thyristor Family), SCRs are made of two transistors thats why they PNPN or NPNP devices. The three important parts of transistor are - Emitter, Collector & Base. & the Three Important parts of SCR are - Anode, Cathode & Gate. Use of SCRs- rectification of high power AC & power control applications, such as lamp dimming, regulators and motor control. Use of Transistors - switch, audio, high voltage, amplifiers, switcher
2 transistor analogy for scr and derivation for expression of anode current?
a thyristor can be considered as two complementary transistors , one pnp- transistor, and other npn transistor
Why doesn't an SCR switch off once it turns on even after reducing gate potential?
A thyristor or silicon controlled rectifier (SCR), as they are sometimes known, consists of two transistors. A pulse on the gate turns on the second transistor which then turns on the first transistor in the combination. Turning on the first transistor enables anode current to flow and maintains a base current for the second transistor which keeps it on.See the Related link for an equivalent circuit for an SCR or thyristor.
What happens if voltage is constant and current is varying when an scr triggers?
Even if the current is varying,as long as the current reaches the value required to trigger the SCR, it will snap into operation. The SCR will remain in operation until the current through it drops to a value below the holding current.
How does a triac differ from SCR?
An SCR is a rectifier and can only conduct in one direction (half wave).A Triac can conduct in both directions (full wave).
What does a thyristor works as a circuit breaker?
A thyristor is a type of semi-conductor and is used in a circuit to control the application of electrical power to a load. They are often found as the switching element in light dimmers and can be used as control elements in power supplies (variable or regulated). Types of thyristors are diacs, triacs, sidacs and SCRs (silicon controlled rectifier).
What is conduction angle in SCR?
The conduction angle in an SCR is the phase angle relative to the power line at which point the gate is fired to commit the anode to conduct to the cathode. By varying the conduction angle, you can change the average power transferred by the SCR.
Is SCR better or Power BJT?
neither is better, it depends on purpose
What is the advantage of an IGBT rectifier compared to an SCR?
An insulated-gate bipolar transistor (IGBT) uses relatively high frequency switching and pulse width modulation (PWM) technology for voltage and current regulation whilst a silicon controlled rectifier (SCR) uses relatively low frequency switching and phase shift technology. Because of the relatively high frequency of operation, the transformers used in circuits having IGBT scan be much smaller in size and lighter in weight, therefore overall a IGBT-based power control circuit can be made much smaller in size, lighter in weight, more energy efficient and more cost effective compared to SCR-based control ciruits. Apart from those advantages, because the cost of manufacturing IGBTs is now lower than SCRs, IGBTs are rapidly replacing SCRs for power control applications.
What is optocopler?
A: It is an IC which contain an led which will couple the input to another device within the package it can be a transistor a triac scr and so forth. is main purpose in application is to isolate the source from the output.
Why does a SCR have negative resistance?
Whenever you measure resistance, the resistance itself cannot be negative!When an SCR (Semiconductor Controlled Rectifier) is not conducting, it has a high resistance between its anode and its cathode. When its gate is triggered and the SCR is conducting, it has a low resistance between its anode and its cathode.For more information about SCRs, see the answer to the Related Question (for which a link is shown below) and also the Related Link.
How can you tell which is the gate terminal on an SCR?
Since the gate needs very small amount of current for operation the small terminal is the gate.
