In the context of electronic systems, particularly amplifiers, open-loop and closed-loop gains refer to different ways of handling signal amplification.
### Open-Loop Gain:
- **Definition**: The open-loop gain is the amplification factor of an amplifier when there is no feedback applied. In other words, it's the gain of the amplifier with its input directly connected to the output without any feedback network.
- **Characteristics**: It is usually very high and can be unstable. The performance of the amplifier can vary significantly with changes in temperature or component values because there's no feedback to stabilize the gain.
### Closed-Loop Gain:
- **Definition**: The closed-loop gain is the amplification factor of an amplifier when feedback is applied. Feedback involves routing a portion of the output signal back to the input to control the gain and improve performance.
- **Characteristics**: It is generally more stable and predictable compared to open-loop gain. The feedback network reduces the overall gain but increases stability, accuracy, and bandwidth. Closed-loop gain is less sensitive to variations in the amplifier's components and external conditions.
In summary, open-loop gain is the inherent gain of an amplifier without feedback, while closed-loop gain is the controlled gain of an amplifier with feedback applied.