A non-inverting amplifier is a type of electronic circuit configuration that amplifies an input signal while maintaining the same polarity or phase as the original signal. In other words, the output signal is a larger version of the input signal, and it's not inverted or flipped in polarity. This type of amplifier is widely used in various electronic applications, such as audio amplification, signal conditioning, and voltage amplification.
Here's how a non-inverting amplifier works:
Basic Configuration: The core of a non-inverting amplifier consists of an operational amplifier (op-amp) connected with a few external components, primarily two resistors.
Operational Amplifier (Op-Amp): The op-amp is a high-gain, differential voltage amplifier with two input terminals (inverting and non-inverting) and a single output terminal. The key characteristic of an ideal op-amp is that it tries to keep the voltage between its inverting (-) and non-inverting (+) inputs at the same level.
Input Signal: The input signal is applied to the non-inverting input terminal (+) of the op-amp. This is the signal you want to amplify.
Feedback Network: The output of the op-amp is connected back to its inverting (-) input terminal through a feedback network, usually a resistor divider network. This forms a closed-loop configuration and determines the amplification factor of the circuit.
Resistor Network: The feedback network consists of two resistors, typically labeled as R1 and R2. R1 is connected between the inverting input and the output, while R2 is connected between the inverting input and ground (or a reference voltage).
Negative Feedback: Due to the negative feedback provided by the resistor network, the op-amp adjusts its output in a way that minimizes the voltage difference between its inverting and non-inverting inputs.
Voltage Gain: The voltage gain (Av) of the non-inverting amplifier is determined by the ratio of the resistors R1 and R2 and is given by the formula: Av = 1 + (R2 / R1).
Output Signal: The amplified output signal is taken from the output terminal of the op-amp.
Key characteristics of a non-inverting amplifier:
The output voltage is larger than the input voltage and maintains the same polarity.
The gain is determined by the resistor values R1 and R2.
The circuit provides stability and accurate amplification due to negative feedback.
The voltage gain can be easily adjusted by changing the resistor values.
Overall, the non-inverting amplifier is a versatile and commonly used circuit configuration for signal amplification in various electronic applications.