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SCR Applications jojo September - 15 - 2009 27 Comments
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Choose from 1M+ Verified Suppliers. Directly & Get Live Quotes! The ability of an SCR to control large currents to a load by means of small gate current makes the device very useful in switching and control applications. A few of the possible applications for the SCR are listed in the introduction to SCR blog post. Here we will consider six applications of SCR like power control, switching, zero-voltage switching, over-voltage protection, pulse circuits and battery charging regulator.
1. Power Control.
SCR Power Control Circuit Because of the bistable characteristics of semiconductor devices, whereby they can be switched on and off, and the efficiency of gate control to trigger such devices, the SCRs are ideally suited for many industrial applications. SCRs have got specific advantages over saturable core reactors and gas tubes owing to their compactness, reliability, low losses, and speedy turn-on and turn-off. The bistable states (conducting and non-conducting) of the SCR and the property that enables fast transition from one state to the other are made use of in the control of power in both ac and dc circuits.
SCR Phase Control In ac circuits the SCR can be turned-on by the gate at any angle α with respect to applied voltage. This angle α is called the firing angle www.circuitstoday.com/scr-applications
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and power control is obtained by varying the firing angle. This is known as phase control. A simple half-wave circuit is shown in figure a. for illustrating the principle of phase control for an inductive load. The load current, load voltage and supply voltage waveforms are shown in figure b. The SCR will turn-off by natural commutation when the current becomes zero. Angle β is known as the conduction angle. By varying the firing angle a, the rms value of the load voltage can be varied. The power consumed by the load decreases with the increase in firing angle a. The reactive power input from the supply increases with the increase in firing angle. The load current wave-form can be improved by connecting a free-wheeling diode D1, as shown by the dotted line in fig-a. With this diode, SCR will be turned-off as soon as the input voltage polarity reverses. After that, the load current will free wheel through the diode and a reverse voltage will appear across the SCR. The main advantage of phase control is that the load current es through a natural zero point during every half cycle. So, the device turns-off by itself at the end of every conducting period and no other commutating circuit is required. Power control in dc circuits is obtained by varying the duration of on-time and off-time of the device and such a mode of operation is called on-off control or chopper control. Another important application of SCRs is in inverters, used for converting dc into ac. The input frequency is related to the triggering frequency of SCRs in the inverters. Thus, variable frequency supply can be easily obtained and used for speed control of ac motors, induction heating, electrolytic cleaning, fluorescent lighting and several other applications. Because of the large power-handling capacity of the SCRs, the SCR controlled inverter has more or less replaced motor-generator sets and magnetic frequency multipliers for gener ating high frequency at large power ratings.
Operation of Power Control in SCR A commonly used circuit for controlling power in load RL using two SCRs is shown in figure. Potentiometer R controls the angle of conduction of the two SCRs. The greater the resistance of the pot, lesser will be the voltage across capacitors C1 and C2 and hence smaller will be the time duration of conduction of SCR1 and SCR2 during a cycle. During positive half cycle capacitor C2 gets charged through diode D1, pot R, and diode D4. When the capacitor gets fully charged, (charge on the capacitor depending upon the value of R) it discharges through Zener diode Z. This gives a pulse to the primary and thereby secondary of the transformer T2. Thus SCR2, which is forward biased, is turned on and conducts through load RL. During negative half cycle similar action takes place due to charging of capacitor C1 and SCR1 is triggered. Thus power to a load is controlled by using SCRs.
2. Switching. Thyristor, being bistable device is widely used for switching of power signals owing to their long life, high operation speed and freedom from other defects associated with mechanical and electro-mechanical switches.
AC Circuit Breaker using SCR Figure shows a circuit in which two SCRs are used for making and breaking an ac circuit. The input voltage is alternating and the trigger pulses are applied to the gates of SCRs through the control switch S. Resistance R is provided in the gate circuit to limit the gate current while resistors R1 and R2 are to protect the diodes D1 and D2 respectively. For starting the circuit, when switch S is closed, SCR1 will fire at the beginning of the positive half-cycle (the gate trigger current is assumed to be very small) because during positive half cycle SCR1 is forward biased. It will turn-off when the current goes through the zero value. As soon as SCR1 is turned-off, SCR2 will fire since the voltage polarity is already reversed and it gets the proper gate current. The circuit can be broken by opening the switch S. Opening of gate circuit poses no problem, as current through this switch is small. As no further gate signal will be applied to the SCRs when switch S is open, the SCRs will not be triggered and the load current will be zero. The maximum time delay for breaking the circuit is one half-cycle. Thus several hundred amperes of load current can be switched on/off simply by han dling gate current of few mA by an ordinary switch. The above circuit is also called the static or because it does not have any moving part. www.circuitstoday.com/scr-applications
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DC circuit breaker
SCR Application-DC Circuit Breaker As shown in figure, Capacitor C pro vides the required commutation of the main SCR since the cur rent does not have a natural zero value in a dc circuit. When the SCR1 is in conducting state, the load voltage will be equal to the supply voltage and the capacitor C will be charged through resis tor R. The circuit is broken by turning-off SCR1. This is done by firing SCR2, called the auxiliary SCR. Capacitor C discharges through SCR2 and SCR1. This discharge current is in opposite direction to that flowing through SCR1 and when the two become equal SCR2 turns-off. Now capacitor C gets charged through the load and when the capacitor C gets fully charged, the SCR2 tums-off. Thus the circuit acts as a dc circuit breaker. The resistor R is taken of such a value that current through R is lower than that of holding current.
3. Zero Voltage Switching.
SCR Switching Application In some ac circuits it is necessary to apply the voltage to the load when the instantaneous value of this voltage is going through the zero value. This is to avoid a high rate of increase of current in case of purely resistive loads such as lighting and furnace loads, and thereby reduce the generation of radio noise and hot-spot temperatures in the device carrying the load current. The circuit to achieve this is shown in figure. Only half-wave control is used here. The portion of the circuit shown by the dotted lines relates to the negative half cycle. Whatever may be the instant of time when switch S is opened (either during the positive or the nega tive half cycle), only at the begin ning of the following positive half-cycle of the applied voltage SCR1 will be triggered. Similarly, when switch S is closed, SCR1 will stop conducting at the end of the present or previous positive half-cycle and will not get triggered again. Resis tors R3 and R4 are designed on the basis of minimum base and gate currents required for transistor Q1 and SCR1. Resistors Rl and R2 govern rates of the charging and discharging of capacitor C1 Resis tor R5 is used for preventing large discharge currents when switch S is closed.
4. Over-Voltage Protection.
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SCR Applications - Electronic Circuits and Diagram-Electronics Projects and Design
Over Voltage Circuit Protection SCRs can be employed for protecting other equipment from over-voltages owing to their fast switching action. The SCR employed for protection is connected in parallel with the load. Whenever the voltage exceeds a specified limit, the gate of the SCR will get energized and trigger the SCR. A large current will be drawn from the sup ply mains and voltage across the load will be reduced. Two SCRs are used—one for the positive half-cycle and the other for negative half-cycle, as shown in figure. Resistor R1 limits the short-circuit current when the SCRs are fired. Zener diode D5 in series with resistors Rx and R2 consti tutes a voltage-sensing circuit.
5. Pulse Circuits.
SCR-Pulse Circuit SCRs are used for producing high voltage/current pulses of desired waveform and duration. The capacitor C is charged during the positive half cycle of the input supply and the SCR is triggered during the nega tive half-cycle. The capacitor will discharge through the output circuit, and when the SCR forward current becomes zero, it will turn-off. The output circuit is designed to have discharge current of less than a milli-second duration. The capacitor will again get charged in the following positive half-cycle and the SCR will be triggered again in the negative half-cycle. Thus the frequency of the output pulse will be equal to the frequency of the input supply. For limiting the charging current resistor R is used. High voltage/current pulses can be used in spot welding, electronic ignition in automo biles, generation of large magnetic fields of short duration, and in testing of insulation. 6. Battery Charging Regulator.
Battery Charging Regulator The basic components of the circuits are shown in figure. Diodes D1 and D2 are to establish a full-wave rectified sig nal across SCR1 and the 12 V battery to be charged. When the battery is in dis charged condition, SCR2 is in the off-state as will be clear after discussion. When the full-wave rectified input is large enough to give the required turn-on gate current (controlled by resistor R1), SCR1 will turn on and the charging of the battery will commence. At the commencement of charging of battery, voltage VR determined by the simple volt age-divider circuit is too small to cause 11.0 V zener conduction. In the off-state Zener diode is effectively an open-circuit www.circuitstoday.com/scr-applications
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SCR Applications - Electronic Circuits and Diagram-Electronics Projects and Design
maintaining SCR2 in the off-state because of zero gate current. The capacitor C is included in the circuit to prevent any voltage transients in the circuit from accidentally turning on of the SCR2. As charging continues, the battery voltage increases to a point when VR is large enough to both turn on the 11.0 V Zener diode and fire SCR2. Once SCR2 has fired, the short circuit representation for SCR2 will result in a voltage-divider circuit determined by R1 and R2 that will maintain V2 at a level too small to turn SCR1 on. When this occurs, the battery is fully charged and the open-circuit state of SCR1 will cut off the charging current. Thus the regulator charges the battery whenever the voltage drops and prevents overcharging when fully charged. There are many more applications of SCRs such as in soft start circuits, logic and digital circuits, but it is not possible to discuss all these here.
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27 Responses to “SCR Applications” TerryK says: August 26, 2013 at 5:38 pm What are the Values and Part #’s for the components of the SCR-based “Battery Charging Regulator” circuit ??? Reply v.sudeesh kumar says: August 23, 2013 at 9:28 am very veary fluantly &xlent Reply zulfiqar says: June 30, 2013 at 4:26 pm Very useful circuits for learners of AC switching designers. Reply Kheminder Bhadana says: February 7, 2013 at 9:25 am What’s requirement of electronics in Indian Army? Reply Clement says: December 17, 2012 at 10:39 am pls tell me a project that i can submit in my college. it must be using scr or mosfet. Reply Collins says: July 20, 2012 at 6:34 am And hw can i know if it wil works? Reply Collins says: July 20, 2012 at 6:30 am Hw valid are all these circuit diagram.because i want to start working on them.and a friend is discouraging me that most of them doenst work.please what do i do.advice me. www.circuitstoday.com/scr-applications
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Reply Thiyaga says: June 24, 2012 at 10:18 am what is the practical application of scr in our day to day life? Reply Ryan Castillo says: April 7, 2012 at 1:40 pm Can i used the small voltage from the speaker of telephone to triger the gate of SCR and serve as switch to ring load like 24Vdc/ac ringer bell.Please advie an cicrcuit diagram thnx Reply Elias says: January 12, 2012 at 11:41 pm May I have the value of every comp for the battery charger Reply Aqeel says: January 10, 2012 at 2:29 am Provide knowledge very wel. Reply Phillip says: September 28, 2011 at 1:31 pm What type of background would an expert in SCR come from – are they electronic or some other classification as I need to find someone who can advise on the types of SCR we need for our application? Reply Phillip says: September 28, 2011 at 1:28 pm Great Content and very interesting. Do you know of a system control programmer that could write the software to control the SCR as switches in a voltage regulator? Reply DHinFLo says: August 10, 2011 at 6:32 am I wonder if someone could supply the component values for the AC and DC static circuit breakers. I want to control the output for 250vac and 28vdc power sources. Reply Saturated Quiescent says: July 28, 2011 at 6:27 pm Hello SEETHARAMAN, thank you for the suggestion. we’ll try to fix the circuit that you’ve suggested. thanks! Reply seetharaman says: July 22, 2011 at 9:18 am Hi Quiescent feed the load through a resistance sense the current to the load as the voltage drop across the resistance and use zener for the level and fire another SCR to disconnect the supply to load. Reply www.circuitstoday.com/scr-applications
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Saturated Quiescent says: July 22, 2011 at 3:17 am >>greetings! just wanna ask if that “Over-Voltage Protection” can function as an ‘over-current protection’??? can you give some ideas how will it work? looking forward for your kind suggestions.. thank you! ..Mr. Quiescent Reply SURAJIT SAMANTA says: November 3, 2010 at 7:46 am really it is very helpul for me. Reply Adena Zona says: September 2, 2010 at 5:42 pm The 3 phase electric power is common way of alternating current transmission and it is a type of polyphase system and is the normal way used by electric power distribution grids to distribute power. That looks like exactly the 3 phase alternator I’ve been looking for. Reply seetharaman says: June 16, 2010 at 2:51 am Hi Edgardo this is only an indication of different type of SCR application. a typical cicuit can be seen on http://www.circuitstoday.com/battery-charger-circuit-using-scrthe project Reply Edgardo Diolola says: June 16, 2010 at 12:41 am Good day.. May I know the exact specification on every component if this circuit? (BATERY CHARGING REGULATOR CIRCUIT) Thanks a lot. Reply Edgardo Diolola says: June 16, 2010 at 12:39 am Good day.. May I know the exact specification on every component if this circuit? Thanks a lot. Reply Danny says: April 16, 2010 at 10:08 pm I wonder if you could perhaps help with values to the full wave speed control using 2 SCR’s and caps, diodes and pot to adjust the point on the wave of starting to conduct for both half cycles. I need it to switch currents on 250V AC with currents up to 6A. I am using SCR’s rated at 8A. My circuit veroboard just blew up after 30years. It was a trade test project way back in the 1970′s Reply chandra says: January 23, 2010 at 12:29 am very very well&good. www.circuitstoday.com/scr-applications
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Reply jay clark says: January 21, 2010 at 1:11 am thank u!! Reply Bade3 says: January 1, 2010 at 5:33 pm good circuits , can i get some real circuit for 100 watt ac power controller ? thanks all Reply IFTIKHAR says: September 15, 2009 at 4:16 pm very usefull circuit Reply
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SCR Applications jojo September - 15 - 2009 27 Comments
Inverter 12V 220V 5000W www.alibaba.com
Choose from 1M+ Verified Suppliers. Directly & Get Live Quotes! The ability of an SCR to control large currents to a load by means of small gate current makes the device very useful in switching and control applications. A few of the possible applications for the SCR are listed in the introduction to SCR blog post. Here we will consider six applications of SCR like power control, switching, zero-voltage switching, over-voltage protection, pulse circuits and battery charging regulator.
1. Power Control.
SCR Power Control Circuit Because of the bistable characteristics of semiconductor devices, whereby they can be switched on and off, and the efficiency of gate control to trigger such devices, the SCRs are ideally suited for many industrial applications. SCRs have got specific advantages over saturable core reactors and gas tubes owing to their compactness, reliability, low losses, and speedy turn-on and turn-off. The bistable states (conducting and non-conducting) of the SCR and the property that enables fast transition from one state to the other are made use of in the control of power in both ac and dc circuits.
SCR Phase Control In ac circuits the SCR can be turned-on by the gate at any angle α with respect to applied voltage. This angle α is called the firing angle www.circuitstoday.com/scr-applications
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and power control is obtained by varying the firing angle. This is known as phase control. A simple half-wave circuit is shown in figure a. for illustrating the principle of phase control for an inductive load. The load current, load voltage and supply voltage waveforms are shown in figure b. The SCR will turn-off by natural commutation when the current becomes zero. Angle β is known as the conduction angle. By varying the firing angle a, the rms value of the load voltage can be varied. The power consumed by the load decreases with the increase in firing angle a. The reactive power input from the supply increases with the increase in firing angle. The load current wave-form can be improved by connecting a free-wheeling diode D1, as shown by the dotted line in fig-a. With this diode, SCR will be turned-off as soon as the input voltage polarity reverses. After that, the load current will free wheel through the diode and a reverse voltage will appear across the SCR. The main advantage of phase control is that the load current es through a natural zero point during every half cycle. So, the device turns-off by itself at the end of every conducting period and no other commutating circuit is required. Power control in dc circuits is obtained by varying the duration of on-time and off-time of the device and such a mode of operation is called on-off control or chopper control. Another important application of SCRs is in inverters, used for converting dc into ac. The input frequency is related to the triggering frequency of SCRs in the inverters. Thus, variable frequency supply can be easily obtained and used for speed control of ac motors, induction heating, electrolytic cleaning, fluorescent lighting and several other applications. Because of the large power-handling capacity of the SCRs, the SCR controlled inverter has more or less replaced motor-generator sets and magnetic frequency multipliers for gener ating high frequency at large power ratings.
Operation of Power Control in SCR A commonly used circuit for controlling power in load RL using two SCRs is shown in figure. Potentiometer R controls the angle of conduction of the two SCRs. The greater the resistance of the pot, lesser will be the voltage across capacitors C1 and C2 and hence smaller will be the time duration of conduction of SCR1 and SCR2 during a cycle. During positive half cycle capacitor C2 gets charged through diode D1, pot R, and diode D4. When the capacitor gets fully charged, (charge on the capacitor depending upon the value of R) it discharges through Zener diode Z. This gives a pulse to the primary and thereby secondary of the transformer T2. Thus SCR2, which is forward biased, is turned on and conducts through load RL. During negative half cycle similar action takes place due to charging of capacitor C1 and SCR1 is triggered. Thus power to a load is controlled by using SCRs.
2. Switching. Thyristor, being bistable device is widely used for switching of power signals owing to their long life, high operation speed and freedom from other defects associated with mechanical and electro-mechanical switches.
AC Circuit Breaker using SCR Figure shows a circuit in which two SCRs are used for making and breaking an ac circuit. The input voltage is alternating and the trigger pulses are applied to the gates of SCRs through the control switch S. Resistance R is provided in the gate circuit to limit the gate current while resistors R1 and R2 are to protect the diodes D1 and D2 respectively. For starting the circuit, when switch S is closed, SCR1 will fire at the beginning of the positive half-cycle (the gate trigger current is assumed to be very small) because during positive half cycle SCR1 is forward biased. It will turn-off when the current goes through the zero value. As soon as SCR1 is turned-off, SCR2 will fire since the voltage polarity is already reversed and it gets the proper gate current. The circuit can be broken by opening the switch S. Opening of gate circuit poses no problem, as current through this switch is small. As no further gate signal will be applied to the SCRs when switch S is open, the SCRs will not be triggered and the load current will be zero. The maximum time delay for breaking the circuit is one half-cycle. Thus several hundred amperes of load current can be switched on/off simply by han dling gate current of few mA by an ordinary switch. The above circuit is also called the static or because it does not have any moving part. www.circuitstoday.com/scr-applications
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DC circuit breaker
SCR Application-DC Circuit Breaker As shown in figure, Capacitor C pro vides the required commutation of the main SCR since the cur rent does not have a natural zero value in a dc circuit. When the SCR1 is in conducting state, the load voltage will be equal to the supply voltage and the capacitor C will be charged through resis tor R. The circuit is broken by turning-off SCR1. This is done by firing SCR2, called the auxiliary SCR. Capacitor C discharges through SCR2 and SCR1. This discharge current is in opposite direction to that flowing through SCR1 and when the two become equal SCR2 turns-off. Now capacitor C gets charged through the load and when the capacitor C gets fully charged, the SCR2 tums-off. Thus the circuit acts as a dc circuit breaker. The resistor R is taken of such a value that current through R is lower than that of holding current.
3. Zero Voltage Switching.
SCR Switching Application In some ac circuits it is necessary to apply the voltage to the load when the instantaneous value of this voltage is going through the zero value. This is to avoid a high rate of increase of current in case of purely resistive loads such as lighting and furnace loads, and thereby reduce the generation of radio noise and hot-spot temperatures in the device carrying the load current. The circuit to achieve this is shown in figure. Only half-wave control is used here. The portion of the circuit shown by the dotted lines relates to the negative half cycle. Whatever may be the instant of time when switch S is opened (either during the positive or the nega tive half cycle), only at the begin ning of the following positive half-cycle of the applied voltage SCR1 will be triggered. Similarly, when switch S is closed, SCR1 will stop conducting at the end of the present or previous positive half-cycle and will not get triggered again. Resis tors R3 and R4 are designed on the basis of minimum base and gate currents required for transistor Q1 and SCR1. Resistors Rl and R2 govern rates of the charging and discharging of capacitor C1 Resis tor R5 is used for preventing large discharge currents when switch S is closed.
4. Over-Voltage Protection.
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Over Voltage Circuit Protection SCRs can be employed for protecting other equipment from over-voltages owing to their fast switching action. The SCR employed for protection is connected in parallel with the load. Whenever the voltage exceeds a specified limit, the gate of the SCR will get energized and trigger the SCR. A large current will be drawn from the sup ply mains and voltage across the load will be reduced. Two SCRs are used—one for the positive half-cycle and the other for negative half-cycle, as shown in figure. Resistor R1 limits the short-circuit current when the SCRs are fired. Zener diode D5 in series with resistors Rx and R2 consti tutes a voltage-sensing circuit.
5. Pulse Circuits.
SCR-Pulse Circuit SCRs are used for producing high voltage/current pulses of desired waveform and duration. The capacitor C is charged during the positive half cycle of the input supply and the SCR is triggered during the nega tive half-cycle. The capacitor will discharge through the output circuit, and when the SCR forward current becomes zero, it will turn-off. The output circuit is designed to have discharge current of less than a milli-second duration. The capacitor will again get charged in the following positive half-cycle and the SCR will be triggered again in the negative half-cycle. Thus the frequency of the output pulse will be equal to the frequency of the input supply. For limiting the charging current resistor R is used. High voltage/current pulses can be used in spot welding, electronic ignition in automo biles, generation of large magnetic fields of short duration, and in testing of insulation. 6. Battery Charging Regulator.
Battery Charging Regulator The basic components of the circuits are shown in figure. Diodes D1 and D2 are to establish a full-wave rectified sig nal across SCR1 and the 12 V battery to be charged. When the battery is in dis charged condition, SCR2 is in the off-state as will be clear after discussion. When the full-wave rectified input is large enough to give the required turn-on gate current (controlled by resistor R1), SCR1 will turn on and the charging of the battery will commence. At the commencement of charging of battery, voltage VR determined by the simple volt age-divider circuit is too small to cause 11.0 V zener conduction. In the off-state Zener diode is effectively an open-circuit www.circuitstoday.com/scr-applications
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maintaining SCR2 in the off-state because of zero gate current. The capacitor C is included in the circuit to prevent any voltage transients in the circuit from accidentally turning on of the SCR2. As charging continues, the battery voltage increases to a point when VR is large enough to both turn on the 11.0 V Zener diode and fire SCR2. Once SCR2 has fired, the short circuit representation for SCR2 will result in a voltage-divider circuit determined by R1 and R2 that will maintain V2 at a level too small to turn SCR1 on. When this occurs, the battery is fully charged and the open-circuit state of SCR1 will cut off the charging current. Thus the regulator charges the battery whenever the voltage drops and prevents overcharging when fully charged. There are many more applications of SCRs such as in soft start circuits, logic and digital circuits, but it is not possible to discuss all these here.
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Posted in Tutorials Tags: SCR, Thyristors
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27 Responses to “SCR Applications” TerryK says: August 26, 2013 at 5:38 pm What are the Values and Part #’s for the components of the SCR-based “Battery Charging Regulator” circuit ??? Reply v.sudeesh kumar says: August 23, 2013 at 9:28 am very veary fluantly &xlent Reply zulfiqar says: June 30, 2013 at 4:26 pm Very useful circuits for learners of AC switching designers. Reply Kheminder Bhadana says: February 7, 2013 at 9:25 am What’s requirement of electronics in Indian Army? Reply Clement says: December 17, 2012 at 10:39 am pls tell me a project that i can submit in my college. it must be using scr or mosfet. Reply Collins says: July 20, 2012 at 6:34 am And hw can i know if it wil works? Reply Collins says: July 20, 2012 at 6:30 am Hw valid are all these circuit diagram.because i want to start working on them.and a friend is discouraging me that most of them doenst work.please what do i do.advice me. www.circuitstoday.com/scr-applications
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SCR Applications - Electronic Circuits and Diagram-Electronics Projects and Design
Reply Thiyaga says: June 24, 2012 at 10:18 am what is the practical application of scr in our day to day life? Reply Ryan Castillo says: April 7, 2012 at 1:40 pm Can i used the small voltage from the speaker of telephone to triger the gate of SCR and serve as switch to ring load like 24Vdc/ac ringer bell.Please advie an cicrcuit diagram thnx Reply Elias says: January 12, 2012 at 11:41 pm May I have the value of every comp for the battery charger Reply Aqeel says: January 10, 2012 at 2:29 am Provide knowledge very wel. Reply Phillip says: September 28, 2011 at 1:31 pm What type of background would an expert in SCR come from – are they electronic or some other classification as I need to find someone who can advise on the types of SCR we need for our application? Reply Phillip says: September 28, 2011 at 1:28 pm Great Content and very interesting. Do you know of a system control programmer that could write the software to control the SCR as switches in a voltage regulator? Reply DHinFLo says: August 10, 2011 at 6:32 am I wonder if someone could supply the component values for the AC and DC static circuit breakers. I want to control the output for 250vac and 28vdc power sources. Reply Saturated Quiescent says: July 28, 2011 at 6:27 pm Hello SEETHARAMAN, thank you for the suggestion. we’ll try to fix the circuit that you’ve suggested. thanks! Reply seetharaman says: July 22, 2011 at 9:18 am Hi Quiescent feed the load through a resistance sense the current to the load as the voltage drop across the resistance and use zener for the level and fire another SCR to disconnect the supply to load. Reply www.circuitstoday.com/scr-applications
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Saturated Quiescent says: July 22, 2011 at 3:17 am >>greetings! just wanna ask if that “Over-Voltage Protection” can function as an ‘over-current protection’??? can you give some ideas how will it work? looking forward for your kind suggestions.. thank you! ..Mr. Quiescent Reply SURAJIT SAMANTA says: November 3, 2010 at 7:46 am really it is very helpul for me. Reply Adena Zona says: September 2, 2010 at 5:42 pm The 3 phase electric power is common way of alternating current transmission and it is a type of polyphase system and is the normal way used by electric power distribution grids to distribute power. That looks like exactly the 3 phase alternator I’ve been looking for. Reply seetharaman says: June 16, 2010 at 2:51 am Hi Edgardo this is only an indication of different type of SCR application. a typical cicuit can be seen on http://www.circuitstoday.com/battery-charger-circuit-using-scrthe project Reply Edgardo Diolola says: June 16, 2010 at 12:41 am Good day.. May I know the exact specification on every component if this circuit? (BATERY CHARGING REGULATOR CIRCUIT) Thanks a lot. Reply Edgardo Diolola says: June 16, 2010 at 12:39 am Good day.. May I know the exact specification on every component if this circuit? Thanks a lot. Reply Danny says: April 16, 2010 at 10:08 pm I wonder if you could perhaps help with values to the full wave speed control using 2 SCR’s and caps, diodes and pot to adjust the point on the wave of starting to conduct for both half cycles. I need it to switch currents on 250V AC with currents up to 6A. I am using SCR’s rated at 8A. My circuit veroboard just blew up after 30years. It was a trade test project way back in the 1970′s Reply chandra says: January 23, 2010 at 12:29 am very very well&good. www.circuitstoday.com/scr-applications
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Reply jay clark says: January 21, 2010 at 1:11 am thank u!! Reply Bade3 says: January 1, 2010 at 5:33 pm good circuits , can i get some real circuit for 100 watt ac power controller ? thanks all Reply IFTIKHAR says: September 15, 2009 at 4:16 pm very usefull circuit Reply
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