Op-Amp Gain Calculator
Calculate voltage gain for inverting and non-inverting operational amplifier configurations
Calculate Op-Amp Gain
Resistance between input signal and inverting terminal
Resistance between output and inverting terminal
Op-Amp Gain Results
Configuration: Inverting Op-Amp
Formula: A = -Rf / Rin
Resistances: 0 / 0
Gain Analysis
Example Calculations
Inverting Amplifier Example
Input Resistance (Rin): 1 kΩ
Feedback Resistance (Rf): 10 kΩ
Formula: A = -Rf / Rin
Calculation: A = -10 kΩ / 1 kΩ = -10
Result: Gain = -10 (20 dB), signal inverted
Non-Inverting Amplifier Example
Resistance R1: 1 kΩ
Feedback Resistance R2: 10 kΩ
Formula: A = 1 + (R2 / R1)
Calculation: A = 1 + (10 kΩ / 1 kΩ) = 1 + 10 = 11
Result: Gain = 11 (20.8 dB), signal not inverted
Op-Amp Configurations
Inverting Configuration
• Input signal → Inverting terminal (-)
• Non-inverting terminal (+) → Ground
• Feedback resistor: Output → Inverting terminal
• Gain = -Rf / Rin
Non-Inverting Configuration
• Input signal → Non-inverting terminal (+)
• Voltage divider: R1 to ground, R2 feedback
• Both resistors connect at inverting terminal
• Gain = 1 + (R2 / R1)
Op-Amp Design Tips
Use precision resistors for accurate gain
Higher gains increase noise and instability
Non-inverting has higher input impedance
Consider op-amp bandwidth limitations
Add compensation for high-frequency stability
Understanding Operational Amplifiers
What is an Op-Amp?
An operational amplifier (op-amp) is a high-gain electronic voltage amplifier with differential inputs. It amplifies the difference between two input voltages and provides a single-ended output. Op-amps are fundamental building blocks in analog electronics.
Key Characteristics
- •Very high input impedance (typically >1 MΩ)
- •Very low output impedance (typically <100 Ω)
- •High open-loop gain (typically 100,000+)
- •Wide bandwidth and good frequency response
Applications
- •Signal amplification and conditioning
- •Active filters and oscillators
- •Mathematical operations (addition, integration)
- •Comparators and voltage references
- •Instrumentation and measurement circuits
Golden Rules: For ideal op-amps with negative feedback: (1) No current flows into input terminals, (2) Voltage difference between inputs is zero.
Inverting vs Non-Inverting
Inverting Configuration
- • Output inverted (180° phase shift)
- • Lower input impedance (≈ Rin)
- • Gain: A = -Rf / Rin
- • Virtual ground at inverting input
Non-Inverting Configuration
- • Output in phase with input
- • Very high input impedance
- • Gain: A = 1 + (R2 / R1)
- • Minimum gain is 1 (unity gain buffer)
Design Considerations
- •Bandwidth: Higher gain reduces bandwidth (GBW product)
- •Stability: Add compensation for high gains
- •Noise: Lower resistance values reduce thermal noise
- •Offset: Input offset voltage affects DC accuracy
- •Power Supply: Consider rail-to-rail operation