SCRની ટર્ન-ઓન પ્રક્રિયા અંગે નીચેનાં વિધાનો ધ્યાનમાં લો:
1. લેચિંગ પ્રવાહ એ લઘુતમ એનોડ પ્રવાહ છે જે ગેટ પલ્સ દૂર કર્યા પછી SCRને ON સ્થિતિમાં જાળવવા જરૂરી છે.
2. હોલ્ડિંગ પ્રવાહ ટર્ન-ઓફ પ્રક્રિયા સાથે સંકળાયેલો છે.
3. ગેટ પલ્સની પહોળાઈ એટલી હોવી જોઈએ કે એનોડ પ્રવાહ હોલ્ડિંગ પ્રવાહથી ઉપર પહોંચે.
4. લેચિંગ પ્રવાહ સામાન્ય રીતે હોલ્ડિંગ પ્રવાહ કરતાં 2 થી 3 ગણો હોય છે.
ઉપર આપેલાં કયાં વિધાનો સાચાં છે?
જવાબ અને પગલાવાર ઉકેલ
B — ફક્ત 1, 2 અને 4. લેચિંગ પ્રવાહ ટ્રિગર પછી તરત SCRને ON રાખવાનો લઘુતમ પ્રવાહ છે; હોલ્ડિંગ પ્રવાહ એ નીચી મર્યાદા છે જેની નીચે SCR બંધ થાય છે (ટર્ન-ઓફ). ગેટ પલ્સ ત્યાં સુધી રહેવી જોઈએ જ્યાં સુધી પ્રવાહ લેચિંગ પ્રવાહ (હોલ્ડિંગ નહીં) થી ઉપર ન જાય.
વિગતવાર ઉકેલ (મૂળ ભાષામાં)
Statement-wise Verification
- Statement 1 - Correct.
Latching current is the minimum anode current required to maintain the SCR in the ON state after the gate pulse is removed.
Latching current is the minimum anode current needed just after triggering so the device stays on when gate drive is removed. - Statement 2 - Correct.
Holding current is associated with the turn-off process.
Holding current is the lower current threshold below which an already-conducting SCR turns off - Statement 3 - Incorrect.
The gate pulse width should be sufficient for the anode current to rise above the holding current.
For reliable turn-on, the anode current must rise above the latching current before the gate pulse is removed - Statement 4 - Correct.
Latching current is typically 2 to 3 times the holding current.
Latching current is normally higher, commonly a few times the holding current.
Core Concept
An SCR is a latching thyristor. Latching current is the minimum anode current needed just after triggering so the device stays on when gate drive is removed. Holding current is the lower current threshold below which an already-conducting SCR turns off; latching current is normally higher, commonly a few times the holding current.
Formula / Key Relationship
I_L > I_H typically.
Why the Other Options Are Wrong
Option A is incorrect because it includes incorrect statement(s) 3 and omits correct statement(s) 4. Option C is incorrect because it omits correct statement(s) 1. Option D is incorrect because it includes incorrect statement(s) 3 and omits correct statement(s) 2.
Exam Shortcut / Approach
Gate pulse must persist until anode current exceeds latching current.
Common Mistake
Do not substitute holding current for latching current during turn-on.
Quick Revision
Latching and Holding Current is linked with SCR Turn-On, Thyristors and Power Electronics. Gate pulse must persist until anode current exceeds latching current.
Regarding the turn-on process of an SCR, consider the following statements:
1. Latching current is the minimum anode current required to maintain the SCR in the ON state after the gate pulse is removed.
2. Holding current is associated with the turn-off process.
3. The gate pulse width should be sufficient for the anode current to rise above the holding current.
4. Latching current is typically 2 to 3 times the holding current.
Which of the statements given above are correct?
Answer & step-by-step solution
Latching current is the minimum anode current needed just after triggering so the device stays on when gate drive is removed. Holding current is the lower current threshold below which an already-conducting SCR turns off; latching current is normally higher, commonly a few times the holding current.
Exam focus: Gate pulse must persist until anode current exceeds latching current. Common trap: Do not substitute holding current for latching current during turn-on.
Statement-wise Verification
- Statement 1 - Correct.
Latching current is the minimum anode current required to maintain the SCR in the ON state after the gate pulse is removed.
Latching current is the minimum anode current needed just after triggering so the device stays on when gate drive is removed. - Statement 2 - Correct.
Holding current is associated with the turn-off process.
Holding current is the lower current threshold below which an already-conducting SCR turns off - Statement 3 - Incorrect.
The gate pulse width should be sufficient for the anode current to rise above the holding current.
For reliable turn-on, the anode current must rise above the latching current before the gate pulse is removed - Statement 4 - Correct.
Latching current is typically 2 to 3 times the holding current.
Latching current is normally higher, commonly a few times the holding current.
Core Concept
An SCR is a latching thyristor. Latching current is the minimum anode current needed just after triggering so the device stays on when gate drive is removed. Holding current is the lower current threshold below which an already-conducting SCR turns off; latching current is normally higher, commonly a few times the holding current.
Formula / Key Relationship
I_L > I_H typically.
Why the Other Options Are Wrong
Option A is incorrect because it includes incorrect statement(s) 3 and omits correct statement(s) 4. Option C is incorrect because it omits correct statement(s) 1. Option D is incorrect because it includes incorrect statement(s) 3 and omits correct statement(s) 2.
Exam Shortcut / Approach
Gate pulse must persist until anode current exceeds latching current.
Common Mistake
Do not substitute holding current for latching current during turn-on.
Quick Revision
Latching and Holding Current is linked with SCR Turn-On, Thyristors and Power Electronics. Gate pulse must persist until anode current exceeds latching current.
SCR की टर्न-ऑन प्रक्रिया के संबंध में निम्नलिखित कथनों पर विचार कीजिए:
1. लैचिंग धारा वह न्यूनतम एनोड धारा है जो गेट पल्स हटाने के बाद SCR को ON अवस्था में बनाए रखने के लिए आवश्यक है।
2. होल्डिंग धारा टर्न-ऑफ प्रक्रिया से संबंधित है।
3. गेट पल्स की चौड़ाई इतनी होनी चाहिए कि एनोड धारा होल्डिंग धारा से ऊपर पहुँच जाए।
4. लैचिंग धारा सामान्यतः होल्डिंग धारा की 2 से 3 गुना होती है।
ऊपर दिए गए कौन-से कथन सही हैं?
उत्तर और चरणबद्ध हल
B — केवल 1, 2 और 4। लैचिंग धारा ट्रिगर के तुरंत बाद SCR को ON रखने की न्यूनतम धारा है; होल्डिंग धारा वह निचली सीमा है जिसके नीचे SCR बंद हो जाता है (टर्न-ऑफ)। गेट पल्स तब तक रहनी चाहिए जब तक धारा लैचिंग धारा (होल्डिंग नहीं) से ऊपर न जाए।
विस्तृत हल (मूल भाषा में)
Statement-wise Verification
- Statement 1 - Correct.
Latching current is the minimum anode current required to maintain the SCR in the ON state after the gate pulse is removed.
Latching current is the minimum anode current needed just after triggering so the device stays on when gate drive is removed. - Statement 2 - Correct.
Holding current is associated with the turn-off process.
Holding current is the lower current threshold below which an already-conducting SCR turns off - Statement 3 - Incorrect.
The gate pulse width should be sufficient for the anode current to rise above the holding current.
For reliable turn-on, the anode current must rise above the latching current before the gate pulse is removed - Statement 4 - Correct.
Latching current is typically 2 to 3 times the holding current.
Latching current is normally higher, commonly a few times the holding current.
Core Concept
An SCR is a latching thyristor. Latching current is the minimum anode current needed just after triggering so the device stays on when gate drive is removed. Holding current is the lower current threshold below which an already-conducting SCR turns off; latching current is normally higher, commonly a few times the holding current.
Formula / Key Relationship
I_L > I_H typically.
Why the Other Options Are Wrong
Option A is incorrect because it includes incorrect statement(s) 3 and omits correct statement(s) 4. Option C is incorrect because it omits correct statement(s) 1. Option D is incorrect because it includes incorrect statement(s) 3 and omits correct statement(s) 2.
Exam Shortcut / Approach
Gate pulse must persist until anode current exceeds latching current.
Common Mistake
Do not substitute holding current for latching current during turn-on.
Quick Revision
Latching and Holding Current is linked with SCR Turn-On, Thyristors and Power Electronics. Gate pulse must persist until anode current exceeds latching current.
More Thyristors (SCR) questions