Optocoupler
An optocoupler, also called an opto-isolator or optical coupler, is an electronic component that allows an electrical signal to be transferred between two completely electrically isolated circuits by using light as the transmission medium.
It combines a light source (typically an infrared LED) and a light detector (such as a phototransistor or photodiode) in a single package.
How It Works:
- Input side (control circuit): An electric current applied to the LED causes it to emit infrared light.
- Isolation: There is no direct electrical connection between the LED and the detector. The isolation is ensured by a physical gap (often filled with a transparent insulating material).
- Output side (controlled circuit): The light emitted by the LED reaches the light detector. This light activates the detector, which in turn modifies the current or voltage in the output circuit.
Key Advantages of Optocouplers:
The main advantage of an optocoupler is the galvanic isolation it provides. This means there is no direct conductive path between the two circuits, allowing it to:
- Protect sensitive circuits from voltage spikes or high currents coming from the control circuit.
- Eliminate ground loops that can cause noise and interference.
- Adapt different voltage levels between the two circuits.
In Summary:
An optocoupler is a "light bridge" that transmits an electrical signal using light, ensuring complete electrical isolation between the input and output.
Applications:
Optocouplers are widely used in various applications, including:
- Power control isolation
- Digital-to-analog system interfacing
- Sensor isolation
- Switching power supplies
- Motor control