Synth Component

The synth component is a junk item in Fallout 4.

Gameplay
A small device of unknown function found only on Generation 3 synths. It can sometimes be found on corpses of settlers, indicating that they are synths, although it is not clear if they are agents of the Institute or escaped synths who have possibly been freed and memory-wiped by the Railroad.

Roslyn Chambers mentions that there is no physical way to tell a synth from a human without killing them, meaning that the component is located somewhere in the body where it is hidden from her tests. The synth component allows the Institute to "program" synths with vocal commands, as well as allowing the Railroad to memory-wipe freed synths.

Crafting
The synth component can be broken down into its components for crafting:

Locations

 * Carried by Amelia Stockton and Sammy.
 * Dropped upon death by Art, Danse, Jules, K1-98, Magnolia, McDonough, Sturges and Timothy.
 * Random settlement settlers and brahmin may be synths and carry a synth component as well. They seem to join settlements as synths and can randomly turn hostile and attack a settlement later in the game, as well as siding with any Institute forces that attack the settlement.
 * Dropped by DiMA upon death.