Consider the following statements regarding Analog Circuits – Diodes:
1. A diode conducts when forward-biased and blocks current in reverse bias condition ideally.
2. The cut-in voltage for silicon diode is approximately 0.7 V.
3. In reverse biased, small leakage current flows due to minority carriers.
4. Diode behaves as linear element under all operating conditions.
Which of the above statements is/are correct?
Answer & step-by-step solution
It conducts strongly in forward bias after its knee/cut-in region and ideally blocks reverse current; practical reverse current includes a small minority-carrier leakage until breakdown. For a silicon diode, the familiar constant-drop approximation is about 0.7 V. Key relation: Shockley form: I≈I_S(e^(V_D/nV_T)−1).
Exam focus: Use 0.7 V only as a practical silicon approximation. Common trap: A diode is not a linear element over its full operating range.
Statement-wise Verification
- Statement 1 - Correct.
A diode conducts when forward-biased and blocks current in reverse bias condition ideally.
It conducts strongly in forward bias after its knee/cut-in region and ideally blocks reverse current - Statement 2 - Correct.
The cut-in voltage for silicon diode is approximately 0.7 V.
For a silicon diode, the familiar constant-drop approximation is about 0.7 V. - Statement 3 - Correct.
In reverse biased, small leakage current flows due to minority carriers.
Practical reverse current includes a small minority-carrier leakage until breakdown. - Statement 4 - Incorrect.
Diode behaves as linear element under all operating conditions.
The correct principle is: A pn-junction diode is nonlinear.
Core Concept
A pn-junction diode is nonlinear. It conducts strongly in forward bias after its knee/cut-in region and ideally blocks reverse current; practical reverse current includes a small minority-carrier leakage until breakdown. For a silicon diode, the familiar constant-drop approximation is about 0.7 V.
Formula / Key Relationship
Shockley form: I≈I_S(e^(V_D/nV_T)−1).
Why the Other Options Are Wrong
Option A is incorrect because it omits correct statement(s) 3. Option B is incorrect because it includes incorrect statement(s) 4 and omits correct statement(s) 2, 3. Option C is incorrect because it omits correct statement(s) 1.
Exam Shortcut / Approach
Use 0.7 V only as a practical silicon approximation.
Common Mistake
A diode is not a linear element over its full operating range.
Quick Revision
Forward and Reverse Bias of Diode is linked with Diode Characteristics, Semiconductor Diodes and Analog Electronics. Use 0.7 V only as a practical silicon approximation.
एनालॉग परिपथ – डायोड के संबंध में निम्नलिखित कथनों पर विचार कीजिए:
1. आदर्श रूप से डायोड फॉरवर्ड बायस में चालन करता है और रिवर्स बायस में करंट को रोकता है।
2. सिलिकॉन डायोड का कट-इन वोल्टेज लगभग 0.7 V होता है।
3. रिवर्स बायस में अल्पसंख्यक वाहकों (minority carriers) के कारण थोड़ा लीकेज करंट बहता है।
4. डायोड सभी परिस्थितियों में रैखिक (linear) अवयव की तरह व्यवहार करता है।
उपरोक्त में से कौन-सा/से कथन सही है/हैं?
उत्तर और चरणबद्ध हल
डायोड नी (knee)/कट-इन वोल्टेज के बाद फॉरवर्ड बायस में तेज़ी से चालन करता है और आदर्श रूप से रिवर्स करंट रोकता है; व्यवहार में ब्रेकडाउन तक थोड़ा अल्पसंख्यक-वाहक लीकेज करंट बहता है। सिलिकॉन डायोड के लिए लगभग 0.7 V का अनुमान लिया जाता है। मुख्य संबंध: I≈I_S(e^(V_D/nV_T)−1)।
परीक्षा फोकस: 0.7 V केवल सिलिकॉन का व्यावहारिक अनुमान है। सामान्य गलती: डायोड पूरी रेंज में रैखिक अवयव नहीं है।
विस्तृत हल (मूल भाषा में)
Statement-wise Verification
- Statement 1 - Correct.
A diode conducts when forward-biased and blocks current in reverse bias condition ideally.
It conducts strongly in forward bias after its knee/cut-in region and ideally blocks reverse current - Statement 2 - Correct.
The cut-in voltage for silicon diode is approximately 0.7 V.
For a silicon diode, the familiar constant-drop approximation is about 0.7 V. - Statement 3 - Correct.
In reverse biased, small leakage current flows due to minority carriers.
Practical reverse current includes a small minority-carrier leakage until breakdown. - Statement 4 - Incorrect.
Diode behaves as linear element under all operating conditions.
The correct principle is: A pn-junction diode is nonlinear.
Core Concept
A pn-junction diode is nonlinear. It conducts strongly in forward bias after its knee/cut-in region and ideally blocks reverse current; practical reverse current includes a small minority-carrier leakage until breakdown. For a silicon diode, the familiar constant-drop approximation is about 0.7 V.
Formula / Key Relationship
Shockley form: I≈I_S(e^(V_D/nV_T)−1).
Why the Other Options Are Wrong
Option A is incorrect because it omits correct statement(s) 3. Option B is incorrect because it includes incorrect statement(s) 4 and omits correct statement(s) 2, 3. Option C is incorrect because it omits correct statement(s) 1.
Exam Shortcut / Approach
Use 0.7 V only as a practical silicon approximation.
Common Mistake
A diode is not a linear element over its full operating range.
Quick Revision
Forward and Reverse Bias of Diode is linked with Diode Characteristics, Semiconductor Diodes and Analog Electronics. Use 0.7 V only as a practical silicon approximation.
એનાલોગ પરિપથ – ડાયોડ સંબંધિત નીચેના વિધાનો ધ્યાનમાં લો:
1. આદર્શ રીતે ડાયોડ ફોરવર્ડ બાયસમાં વહન કરે છે અને રિવર્સ બાયસમાં કરંટ અટકાવે છે.
2. સિલિકોન ડાયોડનો કટ-ઇન વોલ્ટેજ આશરે 0.7 V હોય છે.
3. રિવર્સ બાયસમાં લઘુમતી વાહકો (minority carriers) ને કારણે થોડો લીકેજ કરંટ વહે છે.
4. ડાયોડ તમામ સ્થિતિમાં રેખીય (linear) ઘટક તરીકે વર્તે છે.
ઉપરોક્તમાંથી કયું/કયા વિધાન સાચું/સાચા છે?
જવાબ અને પગલાવાર ઉકેલ
ડાયોડ ની (knee)/કટ-ઇન વોલ્ટેજ પછી ફોરવર્ડ બાયસમાં ઝડપથી વહન કરે છે અને આદર્શ રીતે રિવર્સ કરંટ અટકાવે છે; વ્યવહારમાં બ્રેકડાઉન સુધી થોડો લઘુમતી-વાહક લીકેજ કરંટ વહે છે. સિલિકોન ડાયોડ માટે આશરે 0.7 V નું અનુમાન લેવાય છે. મુખ્ય સંબંધ: I≈I_S(e^(V_D/nV_T)−1).
પરીક્ષા મુદ્દો: 0.7 V ફક્ત સિલિકોનનું વ્યવહારુ અનુમાન છે. સામાન્ય ભૂલ: ડાયોડ સમગ્ર રેન્જમાં રેખીય ઘટક નથી.
વિગતવાર ઉકેલ (મૂળ ભાષામાં)
Statement-wise Verification
- Statement 1 - Correct.
A diode conducts when forward-biased and blocks current in reverse bias condition ideally.
It conducts strongly in forward bias after its knee/cut-in region and ideally blocks reverse current - Statement 2 - Correct.
The cut-in voltage for silicon diode is approximately 0.7 V.
For a silicon diode, the familiar constant-drop approximation is about 0.7 V. - Statement 3 - Correct.
In reverse biased, small leakage current flows due to minority carriers.
Practical reverse current includes a small minority-carrier leakage until breakdown. - Statement 4 - Incorrect.
Diode behaves as linear element under all operating conditions.
The correct principle is: A pn-junction diode is nonlinear.
Core Concept
A pn-junction diode is nonlinear. It conducts strongly in forward bias after its knee/cut-in region and ideally blocks reverse current; practical reverse current includes a small minority-carrier leakage until breakdown. For a silicon diode, the familiar constant-drop approximation is about 0.7 V.
Formula / Key Relationship
Shockley form: I≈I_S(e^(V_D/nV_T)−1).
Why the Other Options Are Wrong
Option A is incorrect because it omits correct statement(s) 3. Option B is incorrect because it includes incorrect statement(s) 4 and omits correct statement(s) 2, 3. Option C is incorrect because it omits correct statement(s) 1.
Exam Shortcut / Approach
Use 0.7 V only as a practical silicon approximation.
Common Mistake
A diode is not a linear element over its full operating range.
Quick Revision
Forward and Reverse Bias of Diode is linked with Diode Characteristics, Semiconductor Diodes and Analog Electronics. Use 0.7 V only as a practical silicon approximation.
More Semiconductor Diodes questions