Hi I have a question about electronic components. I am a new designer and I have been reading about optoisolators/optocouplers this morning and my understanding is that these components are mainly for designs which contain sensors. But wikipedia also suggests that they can be used for transient, high voltage protection also. I always thought that that was what what the application of the transorb was for. So I would like to know if anyone could help clarify this for me a little?

 

The main idea is the optocoupler provides true electrical isolation, there is no current path from input to output, yet signals can pass through.

This component allows circuits operating at large voltage differences to be safely interconnected.

This is relevant to transient protection if you consider that the isolation blocks a potentially damaging current flow - no path, no current = no damage.

 

That helped a lot, thanks.

 

An optocoupler does not protect against lightning because lightning voltages are so high.

 

An opto isolator provides isolation between its input and output. It does not absorb high transient voltages but can prevent them from being transferred from input to output.

A Transorb acts like a high power zener diode to clip high voltage transients in a circuit. It provides no circuit isolation.