Since no current flows into the non-inverting input terminal the input impedance is infinite (ideal conditions) so zero current will flow through the feedback loop. The op-amps output impedance is very low since an ideal op-amp condition is assumed so is unaffected by changes in load.

Also, the input impedance of the voltage follower circuit is extremely high, typically above 1MΩ as it is equal to that of the operational amplifiers input resistance times its gain ( Rin x A O ). The advantage of the unity gain voltage follower configuration is that it can be used when impedance matching or circuit isolation is more important than voltage or current amplification as it maintains the input signal voltage at its output terminal. This then makes the voltage follower circuit ideal as a constant voltage source or voltage regulator because of its input to output isolation properties. This configuration would produce a special type of the non-inverting amplifier circuit called a Voltage Follower, also known as a “unity gain buffer”.Īs the input signal is connected directly to the non-inverting input of the amplifier the output signal is not inverted resulting in the output voltage being equal to the input voltage, thus Vout = Vin. If we made the feedback resistor, Rƒ equal to zero, ( Rƒ = 0), and resistor R2 equal to infinity, ( R2 = ∞), then the resulting circuit would have a fixed gain of “1” (unity) as all the output voltage is fed back to the inverting input terminal (negative feedback). We can easily convert an inverting operational amplifier configuration into a non-inverting amplifier configuration by simply changing the input connections as shown. If resistor R2 is zero the gain will approach infinity, but in practice it will be limited to the operational amplifiers open-loop differential gain, ( A O ). If the value of the feedback resistor Rƒ is zero, the gain of the amplifier will be exactly equal to one (unity). We can see from the equation above, that the overall closed-loop gain of a non-inverting amplifier will always be greater but never less than one (unity), it is positive in nature and is determined by the ratio of the values of Rƒ and R2.

Multisim bode plot voltage gain