Inverting vs Non Inverting Amplifier
Inverting amplifier and non-inverting amplifier are two amplifiers that are designed using the operational amplifier. Inverting amplifier uses the inverting input of the operational amplifier as the main input while the non-inverting input is being grounded. The non-inverting amplifier uses the non-inverting input of the operational amplifier as the main input while the inverting input is being grounded. Both of these amplifier modes are very important in operational amplifier circuits. These circuits are widely used in adding circuits, multipliers, differentiating circuits, integrating circuits, logic gates, and numerous other circuits designed using the operational amplifier. In this article, we are going to discuss what inverting amplifier and non-inverting amplifier are, their applications, the similarities between these two, and finally the difference between inverting amplifier and non-inverting amplifier.
What is an Inverting Amplifier?
To understand what inverting amplifier is one must first understand what an operational amplifier is. An op-amp has two input terminals, two power inputs and one output terminal. The input terminals are known as inverting input and non-inverting input. An ideal op-amp has a gain of infinity with infinite resistance between input terminals and zero resistance in the output terminal. In practice, the input resistance is very large, and the output resistance is very small. The maximum output voltage of the op-amp is equal to the operating voltage coming from the external power source. Op-amp is a differential amplifier, which means the amplifier amplifies the voltage difference between the inverting input and the non-inverting input.
The inverting amplifier is designed by giving an input to the inverting input and grounding the non-inverting end. The output signal is saturated even for a very small input signal due to the theoretical infinite gain of the op-amp. The output signal is 1800 out of phase (inverted) with the input signal. A feedback resistor and an input resistor are connected to the circuits inorder to lower the gain and stabilize the signal. The inverting amplifier has a linear variation with respect to the inverse of the input resistor when the feedback resistor is fixed.
What is a Non-inverting Amplifier?
Non-inverting amplifier is another mode of amplifier designed using the operational amplifier. The output signal, when an input is given to the non-inverting input, is in phase with the input signal. When a feedback resistor with a negative feedback is given and an input resistor is placed, the amplifier is stabilized. In this mode, the amplifier has a linear relationship between the gain and the inverse of the input resistor, when the feedback resistor is fixed. However, there is a gain value when the feedback resistor is zero. This makes the non-inverting amplifier useless in adding, multiplying, and subtracting circuits.
What is the difference between Inverting Amplifier and Non-inverting Amplifier?
• Inverting amplifier gives an inverted output whereas the non-inverting amplifier gives an output which is in phase with the input signal.
• The gain of the inverting amplifier, when used with a negative feedback, is directly proportional to the ratio of the feedback resistor/ input resistor. The gain of the non-inverting amplifier is also proportional to the above ratio but with an intercept value.