Created by RobCo, protectron robots were designed (as their name suggests) for protection, although they can also be seen being used in a manual labor role as well. Typically used in office-type settings, their secondary programming is modular, making them useful as greeters, ticket collectors, bartenders, celebrity or historical figure impersonators, even sexual partners. Typically used in office settings, a large variety of available synthetic personalities and programming options made them universally useful. RobCo offered personalities like the R04 V9 "office helper" with the ability to process and track office protocols and agendas in real time, RobCo RS3 V4.1.6 "utility helper" with automatic routine download and pest extermination mode, RobCo RX2 V1.16.4 "vault helper," loaded with vault protocols. Other models of public service protectrons include medics which are outfitted with a defibrillator, firemen using an internal cryo gun, police officers with electric shock and melee capabilities and even heavy-duty construction workers utilizing internal nail guns. In terms of combat, protectrons are usually weak and easy to defeat, because of their weak weapons and slow movement speed.
In the Commonwealth, protectrons are usually found in charging pods attached to terminals that must sometimes be hacked to activate them. The terminal software allows for different "personalities" to be uploaded to the unit, which changes the unit's voice dialogue and weapon loadout. The choices are: Default, Subway Steward, Construction Worker, Medical Responder, Firefighter and Law Enforcement.
Some attributes of the protectron's looks were derived from 1950's comic books, which keeps with Fallout's overall retrofuturistic theme.
Many protectrons in various areas have been programmed differently. Other protectrons have even been supplied with sophisticated personalities, such as Primm Slim or Vendortron, but these are exceptions.
A protectron with the basic personality loaded on it can execute "sequences," lists of tasks to complete, such as patrolling an area for intruders. Some sequences may have been added by RobCo Industries, whereas others were written by robotics technicians at locations where they are used. When not in use, a protectron unit is stored in a base pod, which charges its battery. The protectron is connected to its base pod via radio uplink, and the pod is in turn connected to a control terminal or a computer system. Protectrons can be customized via software upgrades to perform specific functions, even outside their purpose. Such is the case with Fisto, a pre-War security bot who can be repurposed for sexual pursuits using the sex-bot holotape from Ralph at Mick & Ralph's, or the computer terminal in Cerulean Robotics for James Garret in Freeside during the quest Wang Dang Atomic Tango.
There is also a non-functional prototype of the protectron named Protect-O-Bot, which can be found in the REPCONN headquarters museum, with wheels rather than normal legs, a dynamo accelerator, and a more car-type design.
Protectrons have about the same amount of health as an average human combatant but are much slower, making them less lethal. Their metal bodies provide them with a decent amount of protection; a DT of 8. They are equipped with a series of three built-in laser emitters, mounted in their right and left "hands," as well as the glowing dome atop their head. Unlike humans, protectrons do not take extra damage from headshots, although certain perks (such as Sniper) still make it advantageous to aim for the head.
Like most robots, protectrons are much rarer in the Mojave Wasteland than in the Capital Wasteland. They are not found wandering the Wasteland at random, and are only encountered protecting a handful of intact pre-War facilities.
Protectrons, being one of the weaker robots in Fallout: New Vegas, can be destroyed with most low-level weapons or explosives. Despite being somewhat more durable than the typical raider, their poor armor means their lifespan is likely to be quite short. They are gray by default, but often come painted or manufactured with colored parts depending on where they are found.
They have three laser weapons built into their frame, one in each arm and another one in their head. They are hardly the best shots, although sustained fire can put a dent in the player character's health. The individual firepower in its laser weapons is greater than a laser rifle.
Like most robots, the protectron has a combat inhibitor on its back. Crippling this part of the robot will cause it to frenzy and start attacking all targets indiscriminately.
The Protectron is one of the weaker robots found in the Mojave Wasteland. They do not pose much of a threat, due to their slow speed as well as their weak damage. They are equipped with hand and head lasers, so if one weapon is disabled, the robot is still combat effective. They are not as commonly found as they were in Fallout 3; in Fallout: New Vegas they only patrol some office buildings and the Securitron vault.
Shipping workers are robots that were designed to automate previously human-held shipping positioned in the Sunset Sarsaparilla headquarters. Two operational examples of this variant are found patrolling the large room of the factory with the bottle cap press machine. The same tactics work on them as well as normal protectrons. Once killed, scrap metal, energy cells and fission batteries may be found on their bodies. Several broken shipping workers are found throughout the headquarters, with each containing the same loot.
These slight tougher variants of the Protectron were the envoy of the Sunset Sarsaparilla headquarters' automated robot security. Three security bots can be found patrolling inside the halls of the Sunset Sarsaparilla plant, defending it's secrets from all outside threats, while others that are already disabled by previous visitors can be searched for ammo and components.
The Mark series of protectrons were an attempt by the Big MT company to reproduce, as well as improve, the protectrons produced by RobCo Industries before the war. The "Mark" that is spawned depends on the player's level. The Mark I protectron is more sturdy than the RobCo models, the one exception being the one for security purposes at Sunset Sarsaparilla Headquarters, but the Mark II upwards are all more durable than other models. However, the firepower on all models remains the same.
Unlike the variants found in the Mojave, protectrons in Big MT have a higher DT.
A construction drone is a type of robot used in the Big MT. They were made as an alternative to human labor to manufacture the various structures and machinery seen in the Big MT. Due to their programming as a defensive robot, they also provide their own jobsite security, and are still operating long after the Great War.
The protectron target drone is a protectron model in the Forbidden Zone dome. They have the unique role of being targets for the X-42 giant robo-scorpion, and thus acting as a distraction that is usable by the Courier in their confrontation with the giant robo-scorpion.
A handful of protectrons can be found guarding a chamber in the basement of the HELIOS One control tower, just in front of the elevator leading up to the mainframe deck.
Depending on the player's level, some protectrons may be part of the robotic execution force inside the Vault 11 sacrificial chamber.
The protectrons of Fallout: New Vegas have a smoother, more automatic voice than those of Fallout 3.
Just like the sentry bots, the protectron has a melee function implemented, but doesn't use it in close combat either because it doesn't have an animation to script it, or because it relies on the more damaging laser weaponry.
Edit
ProtectronBlue 
