0
silicon controlled rectifires are like transistors,in this function.we can adjust load(lights)by adjusting bias voltage by a potentiometer(veriable resester).
ANSWER: It could be an SCR but most likely is a TRIAC that conduct both +/- of the AC cycle. These devices have the ability to conduct if a gate current is present. So some kind of delay is used to fire the triac at certain angle of the ac The delay is a resistor capacitor network where the resistor changes the RC time constant for firring
Wiki User
∙ 13y ago
Add your answer:
Earn +20 pts
How can an SCR be made to conduct?
An SCR has three legs. The anode, cathode, and gate. The control voltage sent to the gate will allow the SCR to conduct.
How do you control high voltage using SCR?
By giving proper gate triggering voltage... it can used to control the high power application like ordinary pn junction diode.
What happens if gate voltage of an ON scr is decreased?
A: Nothing after an SCR conduct the gate has no more control to shut it off. So how do we shut off an SCR two way reverse the voltage on the SCR or reduce the current below the holding current. SCR are not DC friendly once on they stay on until see above
Why scr is called as bidirectional an controlled device?
Because it can control input voltage in both halves of cycle.
What is SCR motor control?
An SCR is a Silicon-Controlled-Rectifier. SCR's are used to turn on the AC supply voltage to a motor part-way into the AC cycle, thus allowing only part of the cycle through. Although the peak voltage reaching the motor may be just as high, the average or RMS value is less, since the voltage is not on as long. This type of control is called phase-angle control, as opposed to frequency control, which VFD's (variable frequency drives) do. Note the word 'rectifier' in the name. An SCR, just like any other diode or rectifier, only conducts in one direction, so for AC motor control, two SCR's must be used, one reversed from the other. One SCR fires during the positive half of the cycle, the other fires during the negative half of the cycle. Once the SCR is turned on, it latches, or stays on for the rest of the cycle. When the AC cycle half completes, and the voltage crosses zero, the SCR turns off. Thus the gate signal is usually a very short pulse, right at the moment the SCR needs to fire. Note that the SCR is not like a transistor. It cannot be turned part way on, it is either on or off. The latching action is also different. Transistors do not latch on by themselves. SCRs can also be used as an on-off controller. In this case, the SCR is either completely off (when the motor is to be stopped), or it is controlled on for the entire cycle (when the motor is to run). This type of control is used to replace the old mechanical relays or contactors. In fact, these controllers are called 'Solid State Relays'. Again, two SCR's are used. A similar device is called the Triac. It works basically the same as an SCR, except it conducts in both directions, so only one is needed instaead of two.
Speed control of motor using SCR?
An SCR chip is commonly used to control the speed of a motor. The speed is controlled using an AC circuit and phase angles.
How do you conduct test on speed control of DC motor using SCR?
Connect the SCR in series with the armature or field and control the firing angle of the SCR which in turns determine the current flowing to the armature or field.
Can you use a SCR instead of a relay to control output wattage of a heater?
Yes, using a method called phase control. This method is also used in dimmer switches to continuously reduce the brightness of lights.
How can an SCR be made to conduct?
An SCR has three legs. The anode, cathode, and gate. The control voltage sent to the gate will allow the SCR to conduct.
What is SCR Give its application?
scr is a silicon control rectifier used to control the rectifing voltage.. its a bidirectional device can use it for both the directions......
How do you control high voltage using SCR?
By giving proper gate triggering voltage... it can used to control the high power application like ordinary pn junction diode.
How scr can control the temperature for electric hot plate?
One way is to use a microcontroller with an output pen set up with hardware PWM into the scr, the scr then controls the heating element of the hotplate. A thermistor can be added for a control feedback loop.
What happens if gate voltage of an ON scr is decreased?
A: Nothing after an SCR conduct the gate has no more control to shut it off. So how do we shut off an SCR two way reverse the voltage on the SCR or reduce the current below the holding current. SCR are not DC friendly once on they stay on until see above
When An SCR conducts appreciable current?
And SCR will conduct appreciable current when it is gated "on" and thus "told" to conduct. A silicon controlled rectifier(SCR) is an electronically controlled DC switch, and the gate is the terminal to which the control voltage is applied. Use the link below to learn more.
What is phase control?
such a control rectifier that control or rectifier single phase. for that purpose we used SCR that is called single phase controlled rectifier.
How does bridge rectifier control a DC motor?
give answer how to control the speed of dc motor using bridge rectifier ? ANSWER: A bridge rectifier by itself does not control anything it merely convert AC into DC. the controlling is done by other means SCR TRIACS AND SERVO loop
Is a SCR a voltage rating device or a current rating device?
Check the databook for the SCR you are using. Without knowing the part number, I can't look it up for you.
