Common-Collector Configuration of a Transistor
Summary
TLDRThe video script discusses the common collector configuration of a transistor, where the collector is common to both the input and output sides. It explains the current relationships, including the base current (Ib) as the control current, and the collector current (Ic) as the main current. The script also covers the graphical representation of the output characteristics, showing the relationship between output current (Ic), emitter current (Ie), and output voltage (V) for different base current levels. It emphasizes the importance of the current amplification factor, denoted by gamma (γ), and how it relates to the change in emitter current to the change in base current. The summary also touches on the practical application of common emitter transistors and their output characteristics, concluding with an exploration of the relationship between alpha (α), beta (β), and gamma (γ) in the context of transistor operation.
Takeaways
- 📌 The last type of transistor configuration discussed is the common collector configuration, also known as the emitter follower.
- 🔌 In common collector configuration, the collector is common to both the input and output sides, with the emitter as the current source and the collector as the current sink.
- 📈 The base current (Ib) is the control current, and the collector current (Ic) is the output current, which is also the current that flows through the load.
- 🔗 The relationship between the output current (Ic) and the output voltage (Vc) is graphically represented, showing how they vary with different input current (Ib) values.
- 🔄 The current gain (α) is the ratio of the collector current to the base current, and it typically ranges from 0.95 to 0.98, which is near unity.
- 🔄 The collector current (Ic) is approximately equal to the base current (Ib) multiplied by α, indicating that the output characteristic of a common emitter transistor is similar to that of a common collector transistor.
- 📊 The graphical relationship between the emitter current and the voltage for various levels of base current is discussed, which is crucial for understanding the transistor's behavior.
- 🔢 The current amplification factor, denoted by γ, is the ratio of the change in emitter current to the change in base current, and it is equal to α times Ib.
- 🔄 The input current (Ib) is equal to the base current plus the collector current, and the collector current (Ic) is equal to α times Ib.
- 🔧 The output characteristic of a common emitter transistor is simplified to Ic = Ib + Ic, which helps in understanding the relationship between input and output currents.
- 🔍 The next lecture will delve into the relationship between α, β, and γ, providing further insights into the operation and characteristics of transistors.
Q & A
What is the common collector configuration in a transistor?
-In a common collector configuration, the collector is common to both the input and the output sides of the transistor circuit.
What are the current components in a common collector configuration?
-The current components in a common collector configuration are the base current (I_B), the emitter current (I_E), and the collector current (I_C).
Why is an NPN transistor used in active mode in this configuration?
-An NPN transistor is used in active mode because the emitter-base junction is forward biased and the collector-base junction is reverse biased, allowing proper amplification.
What is the graphical relation plotted for the output characteristics of a common collector configuration?
-The graphical relation plotted for the output characteristics is between the emitter current (I_E) and the output voltage (V_CE) for different values of input current (I_B).
How is the emitter current (I_E) related to the collector current (I_C) and the base current (I_B)?
-The emitter current (I_E) is equal to the sum of the collector current (I_C) and the base current (I_B), represented as I_E = I_C + I_B.
What is the approximate value of the current gain alpha (α) in a common collector configuration?
-The current gain alpha (α) is approximately between 0.95 to 0.98, which is nearly equal to 1.
How does the collector current (I_C) compare to the emitter current (I_E) in practical purposes?
-For all practical purposes, the collector current (I_C) is nearly equal to the emitter current (I_E) in a common collector configuration.
What is the current amplification factor in a common collector transistor and how is it denoted?
-The current amplification factor in a common collector transistor is denoted by gamma (γ) and it is the ratio of the change in emitter current to the change in base current.
How can the emitter current (I_E) be expressed in terms of alpha (α) and the base current (I_B)?
-The emitter current (I_E) can be expressed as I_E = (1 / (1 - α)) * I_B, where (1 / (1 - α)) is the current amplification factor gamma (γ).
What will be discussed in the next lecture as per the transcript?
-The next lecture will cover the comparison between the current gain parameters alpha (α), beta (β), and gamma (γ).
Outlines
🔍 Understanding Common Emitter Transistor Configuration
This paragraph discusses the common emitter configuration of a transistor, where the collector is common to both the input and output sides. It explains the current relationships, with the base current (Ib) being the control current and the collector current (Ic) being the main current. The paragraph also covers the graphical representation of the output characteristics, plotting the output current (Ic) against the output voltage (Vce) for different base currents (Ib). It emphasizes the importance of the current gain (β), which is near to 1, indicating the relationship between the collector current and the base current.
📈 Current Amplification Factor in Common Emitter Configuration
The second paragraph delves into the current amplification factor, denoted by gamma (γ), in the common emitter configuration of a transistor. It explains that gamma is the ratio of the change in emitter current to the change in base current and is equivalent to the current gain (β) times the base current plus the emitter current. The paragraph simplifies the understanding of the output current by expressing it as a function of the input current, highlighting the relationship between the collector current and the input current. It also sets the stage for the next lecture, which will explore the relationship between alpha (α), beta (β), and gamma (γ).
Mindmap
Keywords
💡Transistor
💡Common Collector Configuration
💡Emitter Current (I_B)
💡Collector Current (I_C)
💡Base Current (I_B)
💡Alpha (α)
💡Output Characteristics
💡Current Amplification Factor (Beta, β)
💡Graphical Relation
💡Common Emitter Configuration
💡Input Characteristics
Highlights
The last type of transistor configuration is the common collector configuration.
In this configuration, the collector is common to both the input and output sides.
The base current (iB) is the input current, and the emitter current (iE) is the output current.
We are using an NPN transistor in active mode where the emitter-base junction is forward biased and the collector-base junction is reverse biased.
The common collector configuration can be represented using the symbol of a transistor.
In the common collector configuration, the output voltage Vout is equal to Vc - Ve.
The graphical relation between the emitter current (iE) and the output voltage (Vc) is plotted for different values of the base current (iB).
The collector current (iC) is nearly equal to the emitter current (iE) since alpha is close to 1.
The output characteristic of a common emitter transistor is similar to the output characteristic of a common collector transistor.
The current amplification factor in a common collector transistor is denoted by gamma (γ).
Gamma is the ratio of the change in emitter current to the change in base current.
The emitter current (iE) is equal to the collector current (iC) plus the base current (iB).
The equation for the collector current is iC = alpha * iE + iB.
By substituting the value of the collector current, the emitter current can be simplified as a function of the base current.
The next lecture will cover the relationship between alpha, beta, and gamma.
Transcripts
द लास्ट टाइप ऑफ ट्रांजिस्टर कॉन्फ़िगरेशन
इज कॉमन कलेक्टर कॉन्फ़िगरेशन यू कैन सी
इन दिस कॉन्फ़िगरेशन कलेक्टर इज कॉमन टू द
इनपुट साइड एंड टू द आउटपुट साइड कलेक्टर
इज कॉमन टू द इनपुट साइड एंड इट इज आल्सो
कॉमन टू द आउटपुट साइड v बब एंड व आर द
बाय सिंग पोटेंशियल्स i बी इज़ द बेस
करेंट आईई इज़ द अमीटर करेंट एंड आईसी इज
द कलेक्टर करेंट वी आर यूजिंग n प ए
ट्रांजिस्टर इन एक्टिव मोड बिकॉज ऑफ दिस
एमिटर बेस जंक्शन इज फॉरवर्ड बायस एंड
कलेक्टर बेस जंक्शन इज रिवर्स बायड वी कैन
आल्सो रिप्रेजेंट द कॉमन कलेक्टर कॉन्फिन
यूजिंग द सिंबल ऑफ ट्रांजिस्टर
आई विल क्विकली ड्रॉ द सिंबल ऑफ
ट्रांजिस्टर
वी आर यूजिंग कॉमन कलेक्टर कॉन्फिन
दैट्ची इज v बी स v बी स एंड द आउटपुट
वोल्टेज द आउटपुट वोल्टेज इज v स v स इज
इक्वल टू v ब प्स v
बसीन पुुंब द आउटपुट करंट इज आ इन केस ऑफ
आउटपुट कैरेक्टरिस्टिक वी प्लॉट द
ग्राफिकल रिलेशन बिटवीन द आउटपुट करंट आईई
एंड द आउटपुट वोल्टेज v स फॉर डिफरेंट
वैल्यूज ऑफ इनपुट करेंट आई बी सो वी हैव द
ग्राफिकल रिलेशन बिटवीन द एमटर करेंट
वर्सेस वोल्टेज
वसी फॉर वेरियस लेवल्स ऑफ फॉर
वेरियस
लेवल्स ऑफ बेस करंट आई ब नाउ देयर इज वन
वेरी इंपॉर्टेंट
थिंग दैट वी आर गोइंग टू कंक्लूजन
i इज इक्वल टू ए टाइम्स आ अल्फा इज फ्रॉम
0.95 टू 0.98 व्हिच इज नियर इक्वल टू 1 सो
वी कैन से दैट द कलेक्टर करंट इज नियर
इक्वल टू द अमीटर करंट सो वी कैन रिप्लेस
दिस एमटर करंट विद द कलेक्टर करंट एंड इफ
यू रिमेंबर द लास्ट प्रेजेंटेशन द
ग्राफिकल रिलेशन बिटवीन द कलेक्टर करंट i
एंड द वोल्टेज v स फॉर वेरियस लेवल्स ऑफ
बेस करंट आई बी इज़ नथिंग बट आउटपुट
कैरेक्टरिस्टिक ऑफ़ कॉमन एमिटर
ट्रांजिस्टर सो फॉर ऑल प्रैक्टिकल पर्पसस
द आउटपुट कैरेक्टरिस्टिक ऑफ़ कॉमन अमीटर
ट्रांजिस्टर इज़ सिमिलर टू द आउटपुट
कैरेक्टरिस्टिक ऑफ़ कॉमन कलेक्टर
ट्रांजिस्टर दिस इज़ वेरी इंपॉर्टेंट
पॉइंट द नेक्स्ट थिंग इज़ द करंट
एमप्लीफिकेशन फैक्टर इन कॉमन कलेक्टर
ट्रांजिस्टर द करंट एमप्लीफिकेशन फैक्टर
इज़ डिनोटेड बाय गामा द करेंट
एमप्लीफिकेशन फैक्टर इज़ डिनोटेड बा गामा
एंड इट इज रेशो ऑफ़ चेंज इन एमिटर करेंट
टू द चेंज इन बेस करंट इट इज इक्वल टू
रेशो ऑफ चेंज इन अमीटर करंट द आउटपुट करंट
टू द चेंज इन बेस करंट द इनपुट करंट वी
ऑलरेडी नो वी ऑलरेडी
नो द अमीटर करंट आ इज इक्वल टू द कलेक्टर
करंट प्लस द बेस करंट एंड द कलेक्टर करंट
i इज इक्वल टू अल्फा टाइम्स आ प् i बी दिस
इज इक्वेशन नंबर वन एंड दिस इज इक्वेशन
नंबर टू आई वांट टू सी हाउ आउटपुट करंट
हाउ आउटपुट करंट दैट इज अमीटर करेंट राइज
एज फंक्शन ऑफ इनपुट करेंट दैट इज बेस
करेंट आई विल यूज दिस टू इक्वेशंस एंड बाय
यूजिंग देम आई हैव आ इक्व टू अल्फा टाइम्स
आ प्स
आबी प्स आई ब आई गट दिस बाय सब्सीट्यूटिंग
द वैल्यू ऑफ कलेक्टर करंट इन द फर्स्ट
इक्वेशन आई कैन फदर सिंपलीफाई दिस एज 1
माइ अल्फा
i इक्वल टू आई ब प्
आबी नाउ आई विल डिवाइड बोथ द साइड्स द
लेफ्ट हैंड साइड एंड द राइट हैंड साइड बाय
1 माइ अल्फा सो वी हैव आ
इक्वल टू 1 डिवाइड बाय 1 माइनस अल्फा आई
बी प्लस 1 डिवाइड बाय 1 माइनस अल्फा आई
सीबीओ 1 डिवाइड बाय 1 माइनस अल्फा इज द
करंट एमप्लीफिकेशन फैक्टर इन द कॉमन
कलेक्टर कन्फेशन दिस मींस आई इज इक्वल टू
गमा टाइम्स आई बी प्स गमा टाइम्स आ बी ओम
सो दिस इज़ व्हाट वी हैव इन कॉमन कलेक्टर
कॉन्फ़िगरेशन ऑफ ए ट्रांजिस्टर इन द
नेक्स्ट लेक्चर आई विल राइवल बिटवीन अल्फा
बीटा एंड गामा सो सी यू इन द नेक्स्ट
प्रेजेंटेशन
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