One reason you will often see an optocoupler preferred in digital systems is because these components have simpler circuit construction and reasonably fast response time, yet they still provide comparable isolation as an optotriac.Ĭontrol one side of an isolated system from the other side From the data in the table, we can see that the two types of components are very similar. The table below provides a comparison of these two types of components for optical isolation. This does mean that a system will need to have power on both sides of the isolation barrier. The idea is to use an input signal to then trigger current flow on the output side. The isolation barrier normally prevents current from flowing between two sides of the component. Optocouplers and optoisolators are both used to pass a signal from one side of a system to another side when there is galvanic isolation.

So which should you use in your design? It depends on the type of signal being passed between two isolated regions in a PCB. These components are less often used for optical isolation, typically because of the simplicity of using an optocoupler. There is another type of optoisolator component that can be used, known as an optotriac. The most common method is with an optocoupler, which uses an LED with a phototransistor to couple a signal across a gap. The simplest way to do this with data and control signals is to use optical coupling. The goal in all of this is to control signal flow and ensure safety.Įven when a PCB uses isolated sections to confine power and data, sometimes signals need to pass between the two regions. The isolated section of the PCB could be further isolated from another board in a larger assembly. Most often, this is used to prevent ESD from passing between one region of a PCB and into another region, where one of the isolated regions might be exposed to the external environment.

Isolation in an electronics design involves separating two sides of an electronic component, or groups of components, to prevent signals from passing between two regions of a PCB.

Dc opto isolator