Wire Spring Relay - Use As Logic

Use As Logic

Wire spring relays could be interconnected to create the typical combinational circuits that were later used in silicon design.

The contacts of one or more relays can be used to drive the coil of another relay. To make an OR gate for example, the contacts of several input relays may be placed in parallel circuits and used to drive the electromagnet of a third relay. This, along with series circuits and more complicated schemes such as multiply wound electromagnets, allows the creation of AND gates, OR gates and Inverters (using the normally closed contact on a relay). Using these simple circuits in combination with De Morgan's Laws, any combinational function can be created using relays.

When output wires are fed back as inputs, the result is a feedback loop or sequential circuit that has the potential to consider its own history. Such circuits are often suitable as memories.