A non-inverting amplifier circuit is an electronic circuit commonly used in analog signal processing to amplify a voltage signal without inverting its polarity. In other words, the output signal remains in phase with the input signal, but its amplitude is increased.
The primary purpose of a non-inverting amplifier is to provide signal amplification while maintaining the same signal polarity. This is particularly useful in scenarios where the original signal's phase needs to be preserved, such as in audio applications or sensor interfacing.
The basic configuration of a non-inverting amplifier consists of an operational amplifier (op-amp) and a few passive components, typically resistors. Here's how it works:
Operational Amplifier (Op-Amp): The op-amp is the core component of the non-inverting amplifier circuit. It is a high-gain, differential amplifier that amplifies the voltage difference between its two input terminals.
Positive Feedback: In a non-inverting amplifier, the input signal is applied to the non-inverting input terminal (+) of the op-amp. The op-amp's inverting input terminal (-) is connected to the circuit's output through a resistor network.
Voltage Divider Network: A resistor network is connected between the op-amp's output and inverting input terminal. This network consists of two resistors, with one connected to the inverting input and the other to the output. The non-inverting input is directly connected to the input signal source.
Amplification Gain: The gain (amplification factor) of the non-inverting amplifier is determined by the ratio of the two resistors in the voltage divider network. The larger the ratio, the higher the gain. The gain is given by the formula: Gain = 1 + (R2 / R1), where R1 is the resistor connected to the inverting input and R2 is the resistor connected to the output.
When an input voltage is applied to the non-inverting terminal, the op-amp amplifies the voltage difference between the two input terminals, and the amplified output is produced at the output terminal. Importantly, since the non-inverting input is used, the output signal remains in phase with the input signal, hence the name "non-inverting" amplifier.
In summary, the purpose of a non-inverting amplifier circuit is to provide voltage amplification to a signal without changing its polarity or phase. It finds application in a wide range of electronic systems where maintaining signal phase is critical, such as audio amplifiers, signal conditioning circuits, and measurement devices.