Numerical Example 5: Dc Analysis of BJT | Electronic Devices and Circuits - 1 in EXTC | Summary and Q&A

TL;DR

This video explains how to perform DC analysis on a BJT circuit using self-bias technique.

Key Insights

• 😫 The self-bias technique sets specific supply voltages for the emitter and collector in a BJT circuit.
• 🔠 Input and output KVL should be applied correctly to analyze the circuit accurately.
• ❓ Calculating the values of IB, IC, VCE, VC, and VE requires step-by-step calculations and knowledge of the circuit's parameters.
• 🔠 The value of IB can be determined by rearranging the input KVL equation and substituting the known values.
• ✖️ The relationship between IC and IB is given by the beta value, which is 120 in this case. IC can be calculated by multiplying the value of IB by beta.
• ⚡ The value of VCE can be calculated using the output KVL equation and substituting the values of the supply voltages and IC.
• 💦 VC can be found by subtracting the voltage drop across the 12K resistor from the supply voltage, 16V.
• 🥰 VE can be obtained by subtracting VCE from VC.

Transcript

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Questions & Answers

Q: What is the self-bias technique in a BJT circuit?

The self-bias technique involves setting the emitter supply voltage to -12V and the collector supply voltage to +16V, with the base connected to ground through a resistor.

Q: How do you apply input and output KVL in the self-bias circuit?

The input KVL involves considering the voltage drop across the base-emitter junction, the 15kΩ emitter resistor, and the -12V supply. The output KVL considers the +16V supply, the voltage drop across the 12kΩ resistor, and the VCE.

Q: How do you calculate the value of IB in the self-bias circuit?

By rearranging the input KVL equation and substituting the known values, the value of IB can be calculated. Using this equation: - 9.1kΩ x IB - 0.7V - (121 x 15kΩ x IB) + 12V = 0, the value of IB is found to be 6.195μA.

Q: What is the relationship between IC and IB in the self-bias circuit?

IC is equal to beta times IB, where beta is given as 120. Thus, IC can be calculated by multiplying the value of IB (6.195μA) by 120, resulting in 0.743mA.

Summary & Key Takeaways

• The video discusses the self-bias technique used in a BJT circuit with specific supply voltages.

• The correct approach for input and output Kirchhoff's voltage laws (KVL) is explained.

• The video provides step-by-step calculations to find the values of IB, IC, VCE, VC, and VE.