A non-inverting amplifier is an electronic circuit used to amplify an input signal while preserving its phase. In other words, the output signal of a non-inverting amplifier maintains the same polarity as the input signal. This type of amplifier is commonly used in various applications, such as audio amplification, signal conditioning, and measurement circuits.
The basic circuit diagram of a non-inverting amplifier consists of an operational amplifier (op-amp) connected in a specific configuration along with two resistors. The op-amp is a high-gain voltage amplifier with two inputs, a non-inverting (+) input and an inverting (-) input, and a single output.
Here's how a non-inverting amplifier works:
Configuration: The non-inverting input of the op-amp is connected to the input signal source, and the inverting input is grounded. One resistor is connected between the inverting input and the op-amp output, while another resistor is connected between the inverting input and the ground.
Feedback: The resistor connected between the inverting input and the op-amp output provides a feedback path. This feedback is crucial for determining the amplification factor and the stability of the circuit.
Amplification: The op-amp amplifies the voltage difference between its two inputs. Since the inverting input is grounded in a non-inverting amplifier, the op-amp amplifies the voltage between the non-inverting input and the ground. The gain (amplification factor) of the circuit is determined by the ratio of the resistances. The gain (A) can be calculated using the following formula:
A = 1 + (Rf / R1)
Where:
A is the gain of the amplifier.
Rf is the resistance connected between the inverting input and the op-amp output (feedback resistor).
R1 is the resistance connected between the non-inverting input and the ground.
Output Calculation: The amplified output voltage (Vout) is given by the product of the gain and the input voltage (Vin):
Vout = A * Vin
The output voltage will be greater than the input voltage by the factor of the amplification gain.
It's important to note that non-inverting amplifiers have some limitations, such as saturation of the op-amp output when the input voltage exceeds certain levels. Additionally, the op-amp used should have sufficient bandwidth to accurately reproduce the amplified signal.
Overall, a non-inverting amplifier is a simple and commonly used circuit configuration for signal amplification with the advantage of preserving the phase of the input signal.