Questions tagged [positive-feedback]

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Unstability condition for positive feedback network involving phase change

For positive feedback: \$G=\frac{A}{1-AB}\$ According to Wikipedia, this system is unstable for AB>1. This condition appears to be for the cases when 'A' and 'B' have real values. But in general, A ...
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What is topology of feedback for circuit?

I am confused between Voltage Shunt and Current Shunt Also mention why R2 shouldn't be considered as feedback as it is emitter degeneration resistance Consider the above circuit why can't I consider ...
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How do I find this value for the feedback fraction?

How exactly do I find this value for the feedback fraction Beta? Thank you. omega_0 here is the natural frequency calculated as omega_0 = 1/RC and s is the complex frequency.
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Can oscillations happen even if negative feedback is present?

By OPAMP book says that virtual short is applicable in OPAMP only if negative feedback is present an output is not oscillating.I don't get how oscillations can occur at output if the feedback is ...
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Determine if feedback is negative or positive?

Is there a way to know from how a circuit is designed that is has negative feedback or positive feedback. Here are some examples: Example 1: Example 2:
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Confusion about positive feedback condition in gain equation

Closed loop gain A' of the above op amp system is given as: A' = A / (1 + β*A) where A is the open loop gain which is a positive huge number. Here as a side note, my understanding is that β being ...