Category Archives: Relays

RS485 Relay Output Module for the Raspberry Pi

Although many consider the RS485 relay output module as an archaic protocol, it is still important to the industry. The RS485 protocol allows up to 32 devices to communicate through the same data line over a cable length of up to 4000 feet with a maximum data rate of 10 Mbps. Not many other protocols can equal those numbers. The single board computer, the Raspberry Pi (RBPi) is increasingly finding its way into more and more industrial applications. However, the limiting factor for most compatible Read more [...]

What are Optically Isolated Relays?

Popularly, relays are known to be electromechanical devices. However, engineers today have access to solid-state relays that operate without any electromagnetic or moving parts. Where reliability and performance is paramount, engineers prefer to use solid-state relays to their electromagnetic versions. However, solid-state relays are more expensive. While traditional relays have several mechanical failure modes associated with moving parts, solid-state relays offer several advantages in performance Read more [...]


Relays Relays are electronic or electromechanical switches that operate under the control of an external circuit. Originally when first invented in 1835, electromechanical relays consisted of an electromagnet and a set of contacts. When the electromagnet was energized, it closed the contact by attracting a lever held by a spring. When no current is flowing through the circuit, the electromagnet got demagnetized and the spring pulled back the lever and the circuit was left open. This type of Read more [...]