Sums Based on Positive and Negative Feedback - Oscillators in Basic Electronics - Basic Electronics | Summary and Q&A

TL;DR

This video discusses positive and negative feedback amplifiers, their gain equations, and provides examples of calculating voltage gain with feedback.

Key Insights

• 🔠 A feedback amplifier consists of a feedback network, amplifier input, and output.
• ❎ The gain equation for negative feedback amplifiers is AV- = AV / (1 + βAV), while for positive feedback amplifiers, it is AV- = AV / (1 - βAV).
• 🉐 Calculating the voltage gain with feedback involves plugging the values of AV and β into the gain equation.
• 💱 The type of feedback, either positive or negative, determines how the gain of the amplifier changes.
• 🉐 When feedback is applied, the gain decreases, while when feedback is removed, the gain increases.
• 🉐 The value of β represents the loop gain or feedback gain and determines the amount of feedback applied to the amplifier.
• ⚡ The examples provided demonstrate how to calculate voltage gain with feedback given different values of AV and β.

Transcript

click the bell icon to get latest videos from equator hello friends in today's video we are going to see some examples or sums which are based on positive and negative feedback amplifier or positive or negative feedback so let's begin with the problem now in case of feedback amplifier the feedback amplifier basically consists of feedback network am... Read More

Questions & Answers

Q: How is the gain equation different for negative and positive feedback amplifiers?

In negative feedback, the gain equation is AV- = AV / (1 + βAV), while in positive feedback, the equation is AV- = AV / (1 - βAV). The only difference is the sign of the denominator, with positive feedback having a negative sign.

Q: What is the significance of the value of β in the gain equation?

β represents the loop gain or feedback gain, which determines the amount of feedback applied to the amplifier. A larger value of β would result in a greater feedback effect and a lower gain of the amplifier.

Q: How can the value of voltage gain with negative feedback be calculated?

To calculate the voltage gain with negative feedback, use the equation AV- = AV / (1 + βAV), where AV is the open-loop gain, and β is the loop gain or feedback gain. Plug in the given values to solve for the voltage gain with feedback.

Q: How does the gain of the amplifier change when feedback is applied or removed?

When feedback is applied, the gain of the amplifier decreases. In contrast, when feedback is removed, the gain increases. This behavior is a characteristic of negative feedback amplifiers.

Summary & Key Takeaways

• The video explains that a feedback amplifier consists of a feedback network, amplifier input, and output. The gain of the amplifier can be calculated based on the type of feedback used.

• In negative feedback, the gain equation is AV- = AV / (1 + βAV), where AV is the open-loop gain and β is the loop gain or feedback gain. In positive feedback, the equation is AV- = AV / (1 - βAV), with the difference being the sign of the denominator.

• The video provides example problems of calculating voltage gain with negative feedback and demonstrates how the gain changes when the feedback is applied or removed.