As with any active electronic device, sometimes they simply fail.
They were active devices, using a large infrared light source to illuminate targets.
May 2007 - Patents granted and published for protecting active electronic devices inside a fire safe.
A passive network is a network which does not contain any active device.
Two active devices can communicate in this way as well, using more complex protocols.
Safety scalpels are active devices and therefore the risk of not activating is still significant.
Both active and passive devices may have features which help to prevent test interference.
The scan showed no signs of explosives or active devices.
Both of these would be seen as fit healthy and active by this monitoring device.
The capabilities and economy of power electronics system are determined by the active devices that are available.