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Voltage Follower / Voltage Buffer Using 741 Op - Amp

Voltage Follower or Voltage Buffer is used to issolate an input signal by using an op-amp circuit with the input signal fed to the non-inverting terminal of the op-amp. The gain of a voltage follower or unit gain voltage buffer is one. ie, the exact input is given across the load in a voltage follower circuit without change in phase and polarity of the input signal at the non-inverting terminal of the op-amp.


For a voltage follower circuit the gain should be made unity, to make the gain unity, consider the non-inverting configuration of the op-amp.


we know the gain of a non-inverting amplifier is 1 + (RF/R1)

The circuit must produce the exact input signal at the output without any phase change or polarity reversal. To satisfy this condition, the operational amplifier should satisfy ideal condition. The operational amplifier will satisfy ideal condition ie,  the circuit should have high input impedance and low output impedance.


We replace the non-inverting configuration of the op-amp to ideal op-amp by replacing the input resistance R1 by open circuit, in order to produce high impedance at the input and the feedback resistor RF by a short circuit, in order to produce low impedance at the output.


On applying the above conditions to the non-inverting configuration we get a circuit shown below.
Which will give unit gain, without any change in phase or polarity.
Thank for sharing!