Presentation on bjt configuration
- 1. Presented by: Saruar Chowdhury ID:182-115-013 CSE 45th Presented to Kazi Wohiduzzaman Assistant Professor Department of EEE Course: CSE 131; Basic Electronics Engineering
- 2. Types of transistor configurations. Common Base configuration. Common Emitter configuration. Common Collector configuration. Best one. Alpha , Beta and Gamma. Advantage & Disadvantage of common Emitter configuration. 02
- 3. (i)Common Base (ii)Common Emitter (iii)Common Collector Figure: Bipolar Junction Transistor 03
- 4. Figure: Common Base Configuration This transistor configuration provides a low input impeden- ce while offering a high output impedance. 04
- 5. This transistor configuration is probably the most widely used. The circuit provides a medium input and output impedance levels. Both current and voltage gain can be described as medium, but the output is the inverse of the input, i.e. 180° phase change. This provides a good overall performance and as such it is often thought of as the most widely used configuration. Figure: Common Emitter Configuration 05
- 6. Common collector: This transistor configuration is also known as the emitter follower because the emitter voltage follows that of the base. Offering a high input impedance and a low output impedance it is widely used as a buffer. The voltage gain is unity, although current gain is high. The input and output signals are in phase.In view of these characteristics, the emitter follower configuration is used as a buffer circuit providing a high input impedance to prevent loading of the previous stage, and a low output impedance to drive following stages. Figure: Common Collector Configuration 06
- 7. Figure: BJT Configuration summary table 07
- 8. ALPHA (α): It is a large signal current gain in common bas configuration. It is the ratio of collector current (output current) to the emitter current (input current). Beta (β): It is a current gain factor in the common emitter configuration. It is the ration of collector current (output current) to base current (output current). 10
- 9. Gamma (γ): It is a current gain in common collector configuration and It is the ration of emitter current (output current) to base current (input current). It is also called emitter efficiency that how much current is injected from the emitter to base after recombination of minority charge carriers in base. It’s value is high compared to α,β. 11 Alpha(α),Beta(β) & Gamma(γ)
- 10. Relation between α,β and γ in a transistor 12 α,β and γ are the current gain factors in three CB, CE and CC configurations respectively. Relation between α, β and γ :
- 11. ICB0 is the collector to base reverse saturation current. ICE0 is the collector to emitter reverse saturation current. 13
- 12. 1)It is used in Audio Amplifiers. 2)It is used in Microphones, Radio, and Music Players. 3)It is used in Frequency generation circuit to increase the strength of input signal. 4)It is used to increase the speed of Fans, Motors, and Timer circuits. 14
- 13. 1)It has a tendency to become noisy with age especially in moist climate. 2)The voltage gain reduces at low as well as high frequencies. 3)It provides poor impedance matching and hence it cannot be used as a final stage of an amplifier. 15
- 14. Thank You