Explain the operation of an inverting amplifier circuit.
1 Answer
An inverting amplifier is a basic electronic circuit used to amplify an input signal while inverting its polarity. It is commonly used in analog electronics and is built using an operational amplifier (op-amp) along with a few resistors. The inverting amplifier circuit has a negative feedback configuration, which helps control its gain and stability.
Here's how the inverting amplifier circuit operates:
Operational Amplifier (Op-Amp): The heart of the inverting amplifier circuit is the operational amplifier (op-amp). An op-amp is a high-gain, differential voltage amplifier with two inputs and one output. In the inverting amplifier configuration, the input signal is applied to the inverting terminal (often labeled as the '-' or 'inverting' input), and the output is taken from the same inverting terminal. The non-inverting terminal (usually labeled as the '+' or 'non-inverting' input) is typically connected to a reference voltage, such as ground (0V) in simple cases.
Feedback Resistor (Rf): The feedback resistor is connected between the output of the op-amp and the inverting terminal (input). It establishes a negative feedback loop that influences the circuit's gain and behavior.
Input Resistor (Rin): The input resistor is connected between the inverting terminal and the input signal source. This resistor limits the current flowing into the inverting terminal and helps set the input impedance of the circuit.
Gain Calculation: The gain of the inverting amplifier (A_v) is determined by the ratio of the feedback resistor (Rf) to the input resistor (Rin). Mathematically, the gain is given by:
A_v = -Rf / Rin
The negative sign indicates that the output signal is inverted compared to the input signal.
Operation:
When an input signal (Vin) is applied to the inverting terminal, it creates a voltage difference between the inverting and non-inverting inputs of the op-amp.
The op-amp amplifies this voltage difference, and due to the negative feedback provided by the feedback resistor (Rf), the op-amp adjusts its output voltage to try to nullify this voltage difference.
The output voltage (Vout) of the op-amp increases or decreases as necessary to ensure that the inverting terminal voltage approaches the non-inverting terminal voltage.
Because of the inverting nature of the configuration, the output voltage is the amplified version of the input voltage, but with inverted polarity.
Key characteristics of the inverting amplifier:
The gain can be easily controlled by selecting appropriate resistor values for Rf and Rin.
The input and output voltages are often constrained by the power supply voltage limits of the op-amp.
The circuit inverts the phase of the input signal (180-degree phase shift) due to the op-amp's characteristics.
Overall, the inverting amplifier is a versatile circuit used in various applications, such as audio amplification, signal conditioning, and instrumentation.
Here's how the inverting amplifier circuit operates:
Operational Amplifier (Op-Amp): The heart of the inverting amplifier circuit is the operational amplifier (op-amp). An op-amp is a high-gain, differential voltage amplifier with two inputs and one output. In the inverting amplifier configuration, the input signal is applied to the inverting terminal (often labeled as the '-' or 'inverting' input), and the output is taken from the same inverting terminal. The non-inverting terminal (usually labeled as the '+' or 'non-inverting' input) is typically connected to a reference voltage, such as ground (0V) in simple cases.
Feedback Resistor (Rf): The feedback resistor is connected between the output of the op-amp and the inverting terminal (input). It establishes a negative feedback loop that influences the circuit's gain and behavior.
Input Resistor (Rin): The input resistor is connected between the inverting terminal and the input signal source. This resistor limits the current flowing into the inverting terminal and helps set the input impedance of the circuit.
Gain Calculation: The gain of the inverting amplifier (A_v) is determined by the ratio of the feedback resistor (Rf) to the input resistor (Rin). Mathematically, the gain is given by:
A_v = -Rf / Rin
The negative sign indicates that the output signal is inverted compared to the input signal.
Operation:
When an input signal (Vin) is applied to the inverting terminal, it creates a voltage difference between the inverting and non-inverting inputs of the op-amp.
The op-amp amplifies this voltage difference, and due to the negative feedback provided by the feedback resistor (Rf), the op-amp adjusts its output voltage to try to nullify this voltage difference.
The output voltage (Vout) of the op-amp increases or decreases as necessary to ensure that the inverting terminal voltage approaches the non-inverting terminal voltage.
Because of the inverting nature of the configuration, the output voltage is the amplified version of the input voltage, but with inverted polarity.
Key characteristics of the inverting amplifier:
The gain can be easily controlled by selecting appropriate resistor values for Rf and Rin.
The input and output voltages are often constrained by the power supply voltage limits of the op-amp.
The circuit inverts the phase of the input signal (180-degree phase shift) due to the op-amp's characteristics.
Overall, the inverting amplifier is a versatile circuit used in various applications, such as audio amplification, signal conditioning, and instrumentation.