How to connect relays for logical switching applications?

Relay Logic is all about wiring up Relays for Logical Switching applications. This page demonstrates several simple ways to wire a relay for various applications. Relay Logic provides you with a guide for using NCD relay controllers, and how they can be wired for many types of applications.

How is a relay connected to a control circuit?

When you trigger the relay (by applying the appropriate voltage across the control circuit), the common connection switches to the other side. When you connect your circuit to the NO (normally open) and Common connectors, the circuit remains open until an appropriate voltage is applied to the IN1 connector on the Control circuit.

How are relays and light switches the same?

This sample is exactly the same as a 3-way light switch, the only difference being each physical switch is replaced by a relay. Operationally, it works the same way. Each relay activation will cause the light to toggle. Switching two relays at one time is like flipping 2 switches at once….with the same result.

How are relay controllers used in NCD applications?

Relay Logic provides you with a guide for using NCD relay controllers, and how they can be wired for many types of applications. Use Relay Logic to control the forward or reverse direction of motors.

When you trigger the relay (by applying the appropriate voltage across the control circuit), the common connection switches to the other side. When you connect your circuit to the NO (normally open) and Common connectors, the circuit remains open until an appropriate voltage is applied to the IN1 connector on the Control circuit.

What are the different types of relays and switches?

There are two common types of relays: mechanical relays and solid-state relays. Mechanical relays use an electromagnetic coil and a physical switch; when you apply a voltage, the switch activates.

What happens when no voltage is applied to a relay?

In Figure 1, you see a depiction of a relay in Normally Open (NO) mode. In this configuration, when there’s no voltage applied to the control circuit (the relay at rest portion of the image), the switched circuit is disconnected and current can’t flow through the connection.

Do you need a relay for a microcontroller?

Relays aren’t needed for most microcontroller-based projects as your microcontroller board (whether it’s an Arduino or a full computer system like a Raspberry Pi) will be able to power external devices directly from its I/O ports.