Dry contact意思

"Dry contact" is a term used in electronics and electrical systems to describe a type of connection or switch that does not require electrical continuity or current flow for its operation. In other words, it is a contact that is not connected to a power source or does not have any electrical current running through it.

Dry contacts are commonly found in sensors, switches, and other devices that need to communicate the status of an event or condition to another device without actually providing power to the other device. For example, a dry contact might be used in a security system where a door sensor sends a signal to a control panel to indicate that the door has been opened, but the sensor itself is not powered by the control panel.

In the context of electrical systems, dry contacts are often used in relay circuits where a low-power control signal can activate a high-power relay to switch on or off a load. The control signal is sent through the dry contact, which closes the relay, and the power to the load is switched on or off through a separate set of contacts in the relay.

Dry contacts are also known as "open collector" or "open drain" outputs, and they are commonly used in systems where multiple devices need to communicate with each other or where devices need to be connected to a common bus or line without interfering with each other.