Engineering Q&A
Explain the operation of RC triggering circuit with neat diagram.
in Power Electronics by
retagged by

1 Answer

0 like 0 dislike

RC triggering circuit:

image


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, with lower plate positive. The charging time constant depends upon C and load impedance. If this charging time constant is low, the capacitor gets quickly charged to supply voltage and may attain peak value Vm at -90° as shown in the waveform diagram. At this instant, as both capacitor voltage and supply voltage are equal and opposite, capacitor current is zero. During period after ωt = -90° to ωt = 0°, the supply voltage vs drops from Vm as capacitor discharges. The discharging current passes through supply source, load and R. At ωt = 0°, the capacitor voltage reduces to a value less than Vm, represented by OA in the waveform diagram. After ωt = 0°, the supply voltage become positive, it now helps the discharging current and therefore, the capacitor gets discharged at faster rate. Its negative voltage (lower plate positive) get reduced to zero at a particular instant. The discharging current further continues in the same direction to charge capacitor with upper plate positive. When the capacitor voltage reaches to gate trigger voltage, the SCR is fired. After firing, voltage across SCR drops to low value and hence capacitor voltage also get reduced to low value as shown. The discharging of negatively charged (lower plate positive) capacitor and further charging with upper plate positive is through load and R. Therefore, R determines the discharging and positive charging time-constants. If R is increased, the time-constant get increased and firing is delayed. The SCR can never be triggered at 0° & 180° because the supply voltage is zero and less than finger voltage. 

by

Related questions

1 answer
asked Jun 11, 2019 by anonymous1 | 40 views
1 answer
asked May 10, 2019 by anonymous1 | 31 views
1 answer
asked May 10, 2019 by anonymous1 | 34 views
1 answer
asked May 10, 2019 by anonymous1 | 29 views
1 answer
asked May 10, 2019 by anonymous1 | 24 views
1 answer
asked May 10, 2019 by anonymous1 | 30 views
1 answer
asked May 10, 2019 by anonymous1 | 33 views
1 answer
asked May 10, 2019 by anonymous1 | 35 views
0 answers
asked May 6, 2019 by anonymous1 | 45 views
1 answer
1 answer
asked Aug 15, 2019 by anonymous1 | 13 views
1 answer
asked Jun 11, 2019 by anonymous1 | 43 views
1 answer
asked Sep 4, 2018 by anonymous1 | 22 views
Welcome to electronics2electrical.com, where students and teachers can ask and answer any question. Get help and answers to any engineering problem including Electrical, electronics, mechanical, telecommunication, instrumentation, computer, mathematics, physics etc. Get answers to questions. Help is always 100% free!

Most popular tags

power motor dc circuit transformer voltage current system used phase resistance factor ac load synchronous induction energy electric generator electrical series frequency capacitor between plant line speed transmission use meter type advantages difference single mosfet control function instrument problem magnetic diode amplifier high bjt machine unit source motors and diagram winding shunt field parallel define electricity torque value maximum time relay types arduino supply digital armature applications thyristor working transformers wave on flow operation three coil material instruments state ratio signal emf effect formula efficiency theorem method disadvantages starting microprocessor network test operating direction controlled different logic transistor single-phase scr loss temperature connected rc law force inductance compare measure station wire low conductor principle wattmeter full characteristics measuring constant measurement breaker losses device converter bridge linear materials nuclear matrix flux drive resistivity of machines angle switch free rectifier protection core circuits battery solar gain thermal loop generators open negative analog number lines friction basic reactance short gate pole inverter the conservation diesel iron resistors capacitance engineering using direct main electronic electronics a steam induced relays hysteresis universal transducer computer feedback range distribution work secondary igbt algebra pmmc plants factors capacitors dielectric controller regulation systems design air fault components rotor cable starter oscillator eddy alternator application semiconductor ammeter rl average forces damping rlc connection zener electromagnetic biasing minimum insulation pressure balanced permanent moving errors running copper self analysis impedance stability quality start ideal curve over commutation is 3-phase arc permeability peak bias error fuzzy commutator conductors superposition density mechanical rotation construction measured electrons charge memory inductive two transfer explain fuse methods off back three-phase tariff locomotive installation welding heating rms surge rating generation potentiometer coupled shaded rate capacity storage adc excitation active pure resistor harmonics reluctance microcontroller voltmeter inductor internal 8085 cro reaction insulating overhead hydro resonance traction definition breakers earth

9,199 questions

7,946 answers

158 comments

3,292 users

9,199 questions
7,946 answers
158 comments
3,292 users