Semiconductor relays

Copyright 1997,1998 Tomi Engdahl

NOTE: Very much under construction. Not ment for public use !

This document tries to collect information about semiconductor relays and semiconductor relay circuit to one document which would be useful to electronics professionals and hobbyist. This document is a collection of information from various sources and I have not been able to verify all information. Be aware that there might be errors in the schematics.

Index

General information

• General information
• Typical technical specifications of semiconductor relays
• Information sources

Semiconductor relay releted circuits

• Circuits for driving optocouplers
• Protecting the optoisolator input circuits from reverse voltage
• Computer controlling circuits

AC current semiconductor relay information

• Safety issues
• Radio frequency interference details
• Selecting a TRIAC
• TRIAC failure modes
• Overvoltage protection
• Snubber components in TRIAC circuits
• Overload protection
• Different types of optocouplers for triggering triac
• Circuits with zero voltage starting semiconductor relay
• MOC 3020 based semiconductor relay circuits
• Using normal optoisolator to make semiconductor relay
• Transformer isolated semiconductor relays
• SSR Troubleshooting tips
• Companies which make solid state relays

DC semiconductor relays

Small signal switching