Inverting vs Non-Inverting Op-Amp
| Feature | Inverting Op-Amp | Non-Inverting Op-Amp |
|---|---|---|
| Input connection | Input applied to inverting (-) terminal | Input applied to non-inverting (+) terminal |
| Output phase | 180° out of phase (inverted) | In phase with input |
| Voltage gain | Gain = − (Rf / Rin) | Gain = 1 + (Rf / Rin) |
| Gain sign | Negative | Positive |
| Input impedance | Lower (≈ Rin) | Very high |
| Signal inversion | Yes (flips signal) | No (keeps same shape) |
Inverting Op-Amp
- The input signal goes into the negative (-) terminal
- The positive terminal is usually grounded
- Output is flipped (if input is positive, output becomes negative)
Example: If input = +1V and gain = −5 → output = −5V
Non-Inverting Op-Amp
- The input signal goes into the positive (+) terminal
- Feedback is connected to the negative terminal
- Output follows the same direction as input
Example: If input = +1V and gain = 5 → output = +5V
When to use which?
- Use inverting when you need:
- Signal inversion
- Precise gain control
- Use non-inverting when you need:
- High input impedance
- No signal inversion (e.g., buffering)