A non-inverting amplifier is a type of electronic circuit commonly used in analog signal processing. Its primary function is to amplify an input signal without inverting its polarity. This means that the output signal maintains the same phase as the input signal but is scaled in amplitude.
The basic configuration of a non-inverting amplifier consists of an operational amplifier (op-amp) along with a few passive components such as resistors. Here's how it operates:
Operational Amplifier (Op-Amp): The op-amp is a high-gain voltage amplifier with two input terminals (inverting and non-inverting) and one output terminal. It amplifies the voltage difference between its inputs by a very large factor.
Feedback Network: The key feature of a non-inverting amplifier is the use of a feedback network involving resistors. The non-inverting input (+) of the op-amp is connected directly to the input signal source, while the inverting input (-) is connected to a point within the feedback network.
Feedback Connection: One end of a resistor (R1) is connected to the output of the op-amp, and the other end is connected to the inverting input (-). The junction between the inverting input and R1 is also connected to another resistor (R2) which is connected to the ground (or reference voltage).
Voltage Divider Effect: The feedback network, consisting of R1 and R2, creates a voltage divider. This arrangement ensures that a portion of the output voltage is fed back to the inverting input. As a result, the op-amp adjusts its output in such a way that the voltage at its inverting input is virtually the same as the voltage at its non-inverting input.
Gain Calculation: The amplification factor (gain) of the non-inverting amplifier can be calculated using the following formula:
Gain (A) = 1 + (R2 / R1)
This means that the output voltage is the sum of the input voltage and a fraction of the amplified input voltage.
Output Voltage: The op-amp drives its output to a level that satisfies the feedback conditions, which ensures that the inverting and non-inverting inputs are at the same potential. The output voltage is proportional to the input voltage and can be adjusted by choosing appropriate resistor values for R1 and R2.
In summary, a non-inverting amplifier is designed to amplify an input signal while maintaining its original phase. It achieves this through the use of an op-amp and a feedback network of resistors that create a voltage divider effect. This type of amplifier finds applications in various fields, including audio amplification, signal conditioning, and instrumentation.