Describe triggering of SCR using UJT relaxation oscillator. 

2 Answers

Answer :

Triggering of SCR using UJT relaxation oscillator: 

image


Answer :

I need it's operation

Related questions

Description : With neat diagram explain synchronized UJT triggering circuit.

Last Answer : Line Synchronized UJT triggering circuit: The UJT is almost ideal as a firing device for SCRs. There are 2 main reasons for the compatibility between UJTs and SCRs. Firstly, the UJT produces a ... , the SCR is sure to have the right polarity between the anode and cathode for turning on.

Description : Explain triggering of SCR using opto-coupler. State its advantages. 

Last Answer : Triggering of SCR using opto-coupler:  A simple opto-coupler based triggering circuit for SCR is shown in the figure. An optocoupler or opto-isolator is a combination of light source ... is small size and light weight device. iii)Interfacing with logic circuits is easily possible.

Description : Explain the thermal triggering method of SCR. Enlist different triggering methods of SCR.

Last Answer : Types of Triggering: 1) Forward voltage triggering 2) Thermal triggering (Temperature triggering) 3) Radiation triggering (Light triggering) 4) dv/dt triggering 5) Gate triggering ... generated leakage current increases. This current gets multiplied internally and thyristor is turned on. 

Description : Describe triggering circuit for TRIAC using DIAC.

Last Answer : Triggering circuit for TRIAC using DIAC: DIAC stands for diode alternating current. It's a two terminal four layer bidirectional device. It conducts in both directions. DIAC is used for triggering TRIAC. ... of DIAC to the gate terminal of TRIAC reduces the harmonics.

Description : State the main difference between PUT and UJT.

Last Answer : Difference between PUT and UJT: (i) The intrinsic stand-off ratio of a UJT is fixed hence operating characteristics cannot be alterd. The PUT, on the other hand has operating characteristics that ... time, which allows faster rise in current and provides healthy output pulses as compared to UJT.

Description : Explain the operation of RC triggering circuit with neat diagram.

Last Answer : RC triggering circuit: The RC half-wave triggering circuit is as shown in the figure. During negative halfcycle of supply voltage vs, the capacitor C charges through diode D2 and load, ... be triggered at 0° & 180° because the supply voltage is zero and less than finger voltage. 

Description : Define triggering. List the type of triggering.

Last Answer : Triggering: Triggering means turning-ON of a device from its OFF-state.  Types of Triggering: 1) Forward voltage triggering 2) Thermal triggering (Temperature triggering) 3) Radiation triggering (Light triggering) ... (i) D.C. Gate triggering (ii) A.C. Gate triggering (iii) Pulse Gate triggering

Description : Which triggering is the most reliable?

Last Answer : Gate triggering is most reliable.

Description : Draw and explain the characteristic of UJT. 

Last Answer : UJT Characteristics: The UJT characteristic is emitter voltage versus emitter current characteristic, as shown in the figure. There three operating regions in UJT  1.Cut off region: For ... in IE will place the device into saturation and hence after valley point there is valley point. 

Description : Draw the circuit diagram of battery charger using SCR and explain it’s working.

Last Answer : Battery charger circuit using SCR: The figure shows the battery charger circuit using SCR. A 12V discharged battery is connected in the circuit and switch SW is closed. The singlephase 230V ... not fired. In this way, after full charging, further charging is automatically stopped.

Description : Explain working of AC circuit breaker using SCR with circuit diagram.

Last Answer : AC Circuit Breaker:  The circuit configuration of static AC circuit breaker using SCR is shown in the figure. When switch S' is closed, the SCRs T1 and T2 are fired in positive ... to non-availability of gate current. Thus the maximum time delay for breaking the circuit is one half-cycle.

Description : Temperature controller using SCR

Last Answer : Temperature controller using SCR The temperature control circuit is used to regulate the temperature. Figure shows the temperature control circuit using thermostat as temperature detector and SCR as ... half-cycle and heater gets connected to source to produce heat and raise the temperature.

Description : Draw construction of SCR using two transistor model. Explain its operation.

Last Answer : Two Transistor Model of SCR or Thyristor

Description : Oscillator independent of phase shift is  (1) Relaxation (2) Wein bridge (3) Clapp (4) All of these

Last Answer : Oscillator independent of phase shift is Relaxation 

Description : Compare SCR and TRIAC

Last Answer : SCR TRIAC It is an unidirectional device. It is a bidirectional device. It is turned-on by only positive gate current. It can be turned-on by either ... applications including lamp dimmer, heating control, zero voltage switched AC relay, small AC motor control etc.

Description : How GTO is advantages over SCR

Last Answer : i) It is turned-off by negative gate pulse. ii) No commutation circuit required, reducing the cost, size, weight and volume of the circuit. iii) As commutation choke is not used, the associated acoustic ... turn off time permits high switching frequency. v) It has higher di/dt rating at turn-off. 

Description : Draw a neat labelling V-I characteristics of SCR and explain the region

Last Answer : (i) Latching current: It is the minimum anode current required to maintain the SCR in the conduction state just after turn-on and the gate signal has been removed.  (ii) Holding current: It is the minimum anode current required to hold the conducting SCR in the ON state. 

Description : SCR is more utilized as compared to Triac because it is

Last Answer : SCR is more utilized as compared to Triac because it is available with higher ratings

Description : A 230 V, 50 Hz phase controlled single-phase full-controlled SCR bridge converter draws 15 A constant dc current. If the source inductance is 3 mH, the drop in dc output voltage is (A) 4.5 V (B) 6.75 V (C) 9 V (D) 13.5 V

Last Answer : A 230 V, 50 Hz phase controlled single-phase full-controlled SCR bridge converter draws 15 A constant dc current. If the source inductance is 3 mH, the drop in dc output voltage is 9 V

Description : In a 230 V, 50 Hz single-phase SCR bridge converter operating at a firing delay angle, α and with large R-L load, the input source current is (A) sinusoidal current (B) constant dc current (C) continuous rectangular pulses (D) alternating rectangular pulses

Last Answer : In a 230 V, 50 Hz single-phase SCR bridge converter operating at a firing delay angle, α and with large R-L load, the input source current is alternating rectangular pulses

Description : An SCR without any external connections is considered as (A) two diodes in series (B) three diodes in series (C) two n-p-n transistors in series (D) two p-n-p transistors in series

Last Answer : An SCR without any external connections is considered as three diodes in series

Description : Is a SCR a thyristor?

Last Answer : Yes, SCR is a thyristor. Thyristor is the family and SCR is the member of that family but SCR is universally known as thyristor.

Last Answer : Yes, SCR is a unidirectional switch.

Last Answer : SCR turned off when the anode current falls below holding current.

Description : What is holding current and latching current in SCR? Draw the gate characteristics of an SCR and explain the characteristics. What are the different signals which can be used for turning on SCR by gate control? compare them.

Last Answer : (i) Holding Current: Holding current is defined as the minimum anode current required to maintain conducting SCR in the on-state.  (ii) Latching Current: Latching current is defined as the ... the on-state immediately after the SCR has been turned on and the gate signal has been removed.

Description : What is the use of SCR?

Last Answer : SCR are use in lamp dimming, power regulators, motor control, rectifications of high power AC, control of welding machines and also use as switch these are some uses of silicon controlled rectifier.

Description : Light triggering is mainly used in

Last Answer : Light triggering is mainly used in High voltage direct current transmission

Description : RC triggering is preferred over resistance triggering because (A) it provides triggering at a precise instant (B) it gives a longer duration gate pulse (C) it enables triggering at a larger value of firing angle (D) it protects the SCR against high dv/dt

Last Answer : a

Description : What things you do for relaxation?

Last Answer : Watching let’s play on YouTube.

Description : Is this oscillator adjustable with a screwdriver, and where is the link to prchase it?

Last Answer : answer:@XOIIO Probably a question you should direct to the company. The link below should help. http://www.vectron.com/contact/index.htm

Description : Compare amplifier and oscillator.

Last Answer : Figure shows a block diagram of an amplifier and an oscillator.   An amplifier is a device, which produces an output signal with similar waveform as that of the input. ... is supplied. An oscillator does not require any external signal to start or maintain energy conversion process.

Description : crystal oscillator and its applications.

Last Answer : Need: Any circuit that generates an alternating voltage is called an oscillator. To generate ac Voltage, it takes energy from the dc source. 1. In some applications voltages of low frequency are required where ... generate clock in digital systems.  It is used as sweep circuits in TV and CRO.

Description : Compare RC and LC oscillator.

Last Answer :  RC and LC oscillator

Description : List two types of oscillator, which generates frequency in RF range.

Last Answer : Types of Oscillators generating frequencies in RF range: i) Hartley Oscillator ii) Colpitt’s Oscillator iii) Clapp Oscillator

Description : Draw the circuit diagram of crystal oscillator and explain its working.

Last Answer : To excite a crystal for operation in the series-resonant mode it may be connected as a series element in a feedback path, the crystal impedance is the smallest and the amount of positive feedback is the largest. ... which is good.  The resonant frequency is given as  Fo = 1/( 2 π √LC ) 

Description : Draw and explain Hartley Oscillator circuit diagram.

Last Answer : Function of each component: 1. An NPN transistor connected in a common emitter configuration works as the active device in amplifier stage and CE configuration provides 180°phase shift. 2. R1 and R2 ... circuit to the base-emitter circuit.  The frequency of oscillation is given as-  

Description : Draw and explain RC phase shift Oscillator.

Last Answer : Circuit diagram of RC phase shift oscillator: WORKING: * Circuit consists of a single stage amplifier in common emitter configuration & RC phase shifting network. * R1, R2, RE provides biasing & CE ... . * The phase shift around the loop is 3600 only at one precise frequency.  

Description :  Which of the following is a negative-resistance microwave device for oscillator applications? A) IMPATT Diode B) Gunn Diode C) Snap diode D) Schottky Diode 

Last Answer :  Which of the following is a negative-resistance microwave device for oscillator applications? A) IMPATT Diode B) Gunn Diode C) Snap diode D) Schottky Diode 

Description : In an R-C phase shift oscillator, the minimum no. of R-C networks to be connected in cascade will be -

Last Answer : In an R-C phase shift oscillator, the minimum no. of R-C networks to be connected in cascade will be 3

Description : A Hartley Oscillator is used for generating (A) very low frequency Oscillation (B) radio-frequency Oscillation (C) microwave Oscillation (D) audio-frequency Oscillation

Last Answer : A Hartley Oscillator is used for generating radio-frequency Oscillation

Description : Purpose of Selective Catalytic Reduction (SCR)

Last Answer : Purpose of Selective Catalytic Reduction (SCR) : 1. It reduces Nox 75% to 90% 2. Converts it in to molecular nitrogen and water vapor 3. It reduces HC emission up to 80% 4. It reduces PM emission 20 to 25%.

Description : An inductor is connected in series with SCR to protect it from A) Excessive high voltage B) Excessive high dv/dt C) Excessive high di/dt D) Excessive large forward current 

Last Answer : An inductor is connected in series with SCR to protect it from Excessive high di/dt

Description : The no-load speed of a single-phase SCR bridge converter fed separately excited dc motor operating at a firing delay angle, α and flux, Φ (A) directly proportional to α and Φ (B) ... proportional to α and inversely proportional to Φ (D) directly proportional to Φ and inversely proportional to α

Last Answer : The no-load speed of a single-phase SCR bridge converter fed separately excited dc motor operating at a firing delay angle, α and flux, Φ directly proportional to α and inversely proportional to Φ

Description : In a 3-phase converter circuit during commutation when one SCR in one phase is turned on to turn-off an SCR in another phase, results in (A) voltage notching (B) harmonic distortion (C) voltage sag (D) voltage swell

Last Answer : In a 3-phase converter circuit during commutation when one SCR in one phase is turned on to turn-off an SCR in another phase, results in voltage notching

Description : Draw the circuit and explain the operation of UJT relaxation oscillator. 

Last Answer : Working: When the supply voltage (VCC) is switched ON, the capacitor charges through resistor (R), till the capacitor voltage reaches the voltage level (VP) which is called as peak point voltage. At ... resistor R is shown as a variable resistor. The sweep period is given by the relation

Description : What do you do to relax?

Last Answer : I binge watch YouTubes let’s play and Fluther .

Description : How to become popular, respected, confident, and a generally more relaxed person?

Last Answer : I like teasing authority figures and showing up noonish. Cherry picking assignments while deciding which one’s to do and which ones to “forget” to do.

Description : So what do you usually do during all that procrastinating?

Last Answer : Any kind of “busy” work that is all around what I need to be doing.

Description : What is the fastest way to finish a jigsaw puzzle?

Last Answer : Get a hammer. ;)

Description : Where do you go, or what do you do when things get a bit too much?

Last Answer : The place where I live of course, that is the only place of peace we have (or should have at least).