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Many household dimmers are SCRs. The dimmer control knob or slider actually adjusts at what point along the AC wave the SCR turns on.
If the SCR turns on earlier, and stays on until dropout voltage, it will make the lamp appear brighter than if the SCR was turned on later and stayed on until dropout voltage, and was therefore on for a shorter time each cycle.
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What is ac and DC supplies?
AC supply means the supply voltage is alternating one. Supply has some particular frequency and magnitude. e.g. usual power supply to domestic use DC supply means the supply voltage (or current) is not alternating. It is fixed one. i.e. frequency is zero. e.g. batteries
If an inductor and a switch are connected in parallel through which the current will flow in an AC circuit?
A:The inductor does not allow ac signal to pass through. It blocks ac and passes dc. If the switch is open, then the ac signal wont pass. If the switch is closed, then the ac signal will pass through the switch.AnswerIt is incorrect to say that an inductor 'does not allow' the passage of an alternating current. An a.c. current will pass through an inductor, although the inductor will limit the value of that current due to the inductor's inductive reactance. Inductive reactance, which is expressed in ohms, is directly-proportional to the inductance of the inductor and to the frequency of the supply. The value of the current is determined by dividing the supply voltage by the inductive reactance of the inductor.If the switch is connected in parallel with the inductor, then closing the switch will apply a direct short circuit across the inductor, and the resulting short-circuit current will cause the circuit's protective device (fuse or circuit breaker) to operate.
What is the use of PN diode?
there are many uses. one major use i remember is in rectification i.e convert ac to dc For switch operation
How do vfd's change the AC to dc current and back into AC?
Variable frequency drives use a rectifier to "chop off" the top part of the ac wave, then use capacitors to "fill in" the gaps in the voltage, making a "near dc" power. They use IGBTs, a fancy term for a high speed, high current transistor, or electronic switch, to pulse the "near dc" power out to the motor, in a pattern that appears like ac to the motor.
Why you using DC power supply for capacitor?
Because it does not allow ac to pass through it...
When you connect a full-wave SCR circuit to a 60Hz AC supply how many DC pulastions will you get?
120
Why SCR does not latch in AC circuit?
because it doesnt
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 the use of a regulator?
ac supply converted with dc supply
What is the use of regulator?
ac supply converted with dc supply
What is the working of cycloconverter?
Cycloconverter is a ac to low frequency ac converter.which convert ac to low freq.ac with help of scr.
Why we don't use triac in case of ac controlled rectfier rather than scr?
A TRIAC does not have a symmetrical turn-on point in the opposite quadrant. This will introduce a DC bias, which you probably don't want. You can use an SCR, and then add diodes to allow it to operate in the opposite quadrant, or you can use two SCR's. Alternatively, you can use a DIAC in the TRIAC's gate circuit to balance the turn on point.
What is the working principle of cycloconverter?
Cycloconverter is a ac to low frequency ac converter.which convert ac to low freq.ac with help of scr.
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
How do you get two bright lights and one dim light without a resistor?
1. Use 3 lightbulbs, with a 3 way switch. 2. Use 1 3-way lightbulb with a 3 way switch. 3. Use a diode in series with one bulb to dim it. 4. Use a silicon-controlled rectifier (SCR) with a simple circuit to cut out a certain percentage of each AC wave.
Why scr is used in ac or dc voltage regulator?
The only use of an SCR in a powersupply regulator that I know of is a Crowbar protection circuit to force the breaker to pop if the regulation fails and the powersupply output voltage rises too high.
Does an SCR work on DC or ac?
SCR's are mainly used in AC circuits. They could be used in DC circuits but they then would not be able to turn off. They require the zero crossing of the AC circuit to turn off. Then when positively biased they can be turned back on.
