A non-inverting amplifier is an electronic circuit configuration commonly used in analog signal processing. It is often used to amplify a voltage signal while maintaining the same polarity as the input signal. In this configuration, the output signal is "in phase" with the input signal, meaning that when the input voltage increases, the output voltage also increases.
The basic schematic of a non-inverting amplifier looks like this:
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V_in ------ R1 ---------------+
|
R2
|
+--- V_out
|
GND
Here:
V_in is the input voltage.
R1 is the feedback resistor connected between the inverting (-) input of the op-amp and the output.
R2 is the input resistor connected between the non-inverting (+) input of the op-amp and the ground (GND).
V_out is the output voltage.
GND is the ground reference.
The voltage gain (A) of the non-inverting amplifier is given by the formula:
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A = 1 + (R1 / R2)
Where:
A is the voltage gain of the amplifier.
R1 is the feedback resistor (connected between the inverting input and the output).
R2 is the input resistor (connected between the non-inverting input and ground).
The voltage gain is typically expressed in a ratio form (without units) or in decibels (dB). If the resistances are given in the same units (ohms), the result will be a ratio, and if they are given in kΩ, the result will be in decibels (dB).
For example:
If R1 = 10 kΩ and R2 = 1 kΩ, then the voltage gain would be:
A = 1 + (10 kΩ / 1 kΩ) = 11 (ratio) or approximately 20.8 dB.
Non-inverting amplifiers are widely used in various applications where signal amplification with positive polarity is required. They are commonly used in audio systems, instrumentation, and other signal processing circuits.