A non-inverting amplifier is an electronic circuit used to amplify an input signal while maintaining the same polarity (phase) as the original signal. It's called "non-inverting" because the output signal is not inverted or reversed in phase compared to the input signal. This type of amplifier is commonly used in various applications where signal amplification is needed while preserving the signal's original characteristics.
The basic configuration of a non-inverting amplifier consists of an operational amplifier (op-amp) and a few passive components, typically resistors. Here's a simplified schematic representation:
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Vin ----- R1 ------+
|
| Vout
+--->----/\/\/\---->
| R2
|
|
GND
In this circuit:
Vin is the input signal you want to amplify.
R1 is a resistor connected between the input signal and the inverting input terminal of the op-amp.
R2 is a resistor connected between the inverting input terminal and the output terminal of the op-amp.
Vout is the amplified output signal.
GND represents the ground reference.
The gain of a non-inverting amplifier (Av) is given by the formula:
Av = 1 + (R2 / R1)
Where:
R1 is the resistance of resistor R1.
R2 is the resistance of resistor R2.
The gain calculation is straightforward. The amplified output voltage (Vout) is the input voltage (Vin) multiplied by the gain (Av):
Vout = Vin * Av
Keep in mind that for the circuit to work accurately, the open-loop gain of the operational amplifier should be much greater than the desired closed-loop gain (R2 / R1). Additionally, the resistor values R1 and R2 should be carefully chosen to achieve the desired amplification and meet the requirements of the application.