A hybrid coupler is a passive device used in radio and telecommunications.

Both active and passive devices may have features which help to prevent test interference.

However this no longer represents a passive device.

Flame arresters are passive devices with no moving parts.

These devices are more frequently illegal than passive devices.

The original version is a passive device, Singer part number 28915.

An acoustic mirror is a passive device used to reflect and perhaps to focus (concentrate) sound waves.

In some cases, the term "linear element" may be a more appropriate term than "passive device."

Acoustic mirrors are passive devices used to reflect and perhaps to focus sound waves.

The network isolator is therefore a passive device, and functions without any requirement of an external power supply.