The iPhone's hardware is designed entirely by Apple Inc. in California. While Apple designs its own system-on-a-chip (SoC), including the CPU and GPU, final assembly is outsourced to manufacturing partners, primarily Foxconn and Pegatron, in countries like China and India. This model allows Apple to maintain strict control over its supply chain, intellectual property, and the final product's quality.
Screen and input The touchscreen on the iPhone has increased in size several times over the years, from 3.5 inches on the original iPhone to iPhone 4S, to the current 6.1 and 6.9 inches on the iPhone 16 and 16 Pro Max series. The touch and gesture features of the iPhone are based on technology originally developed by FingerWorks. Most gloves and styli prevent the necessary electrical conductivity; although capacitive styli can be used with iPhone's finger-touch screen. The iPhone 3GS and later also feature a fingerprint-resistant oleophobic coating.
The iPhone has a minimal hardware user interface, with most models featuring five buttons. The only physical menu button is situated directly below the display and is called the "Home button" because its primary function is to close the active app and navigates to the home screen of the interface. Earlier models included a rounded square, reminiscent of the shape of icons on the home screen. However, new models which include Apple's fingerprint recognition feature Touch ID (which use the Home button as the fingerprint sensor) have no symbol. The iPhone X and later, with the exception of the iPhone SE series, do not have a Home button, and include Face ID in place of Touch ID, a facial recognition authentication method.
A multi-function sleep/wake button is located on top of the device on earlier models, and on right of the device from iPhone 6 onwards. It serves as the unit's power button, and also controls phone calls. When a call is received, pressing the sleep/wake button once silences the ringtone, and when pressed twice transfers the call to voicemail. Situated on the left spine are the volume adjustment controls. The iPhone 4 has two separate circular buttons to increase and decrease the volume; all earlier models house two switches under a single plastic panel, known as a rocker switch, which could reasonably be counted as either one or two buttons.
Directly above the volume controls is a ring/silent switch that, when engaged, mutes phone calls ringtones, alert sounds from push notifications, and system sound effects. In later models, this has been replaced by the Action Button that can be used like the original ring/silent switch or programmed to perform a number of different actions.
3D Touch and Haptic Touch
The iPhone 6S and 6S Plus, introduced in 2015, feature 3D Touch displays which allow the screen to recognize how hard it is being pressed using pressure-sensitive multi-touch technology, and a new Taptic Engine to provide haptic feedback. In addition to visual cues, 3D Touch uses the Taptic Engine to provide a tactile sensation relative to the force being applied to the display to indicate to the user that a light or deep press action has been completed. An example of how this technology was used is lightly pressing the screen to preview a photograph and deeply pressing to open it, a feature dubbed 'Peek and Pop' by Apple.
All iPhones starting with the iPhone 6s (with the exception of the first-generation iPhone SE and iPhone XR) had this feature. Starting in 2019 however, 3D Touch was omitted on all iPhones starting with the iPhone 11 and 11 Pro series, and its software features were removed from iOS 13 and later in favour of Haptic Touch. Haptic Touch retains much of the functionality of 3D Touch but cannot detect pressure, as the display lacks integrated capacitive sensors. Actions that previously required a deep press now only require a long press, and the haptic feedback is no longer associated with the applied pressure but rather the touch duration. iPad models that can update to iPadOS 13, along with the first-generation iPhone SE and seventh-generation iPod touch, which previously did not support 3D Touch, simultaneously gained similar Haptic Touch functionality with the iOS 13 and iPadOS 13 updates, although without any haptic feedback.
Sensors
iPhones feature a number of sensors, which are used to adjust the screen based on operating conditions, enable motion-controlled games, location-based services, unlock the phone, and authenticate purchases with Apple Pay, among many other things.
Proximity sensor A proximity sensor deactivates the display and touchscreen when the device is brought near the face during a call. This is done to save battery power and to prevent inadvertent inputs from the user's face and ears. The iPhone's proximity sensors detect the ear and switches off the light, saving power and stopping the face from unintentionally pressing buttons. A phone case, dirt or grime, or a software problem may cause the proximity sensor to malfunction.
Ambient light sensor An ambient light sensor adjusts the display brightness which saves battery power and prevents the screen from being too bright or too dark. True Tone, which is activated by default, uses advanced sensors to change the colour and intensity of the iPhone screen to match the ambient light, resulting in more natural-looking images. The ambient light sensor decides how much light is available around the iPhone and other Apple products, such as the iPod and iPad. The device changes the screen brightness automatically based on this knowledge to save battery life and minimize eye strain.
Accelerometer A 3-axis accelerometer senses the orientation of the phone and changes the screen accordingly, allowing the user to easily switch between portrait and landscape mode. Photo browsing, web browsing, and music playing support both upright and left or right widescreen orientations. Unlike the iPad, the iPhone does not rotate the screen when turned upside-down, with the Home button above the screen, unless the running program has been specifically designed to do so. The 3.0 update added landscape support for still other applications, such as email, and introduced shaking the unit as a form of input (generally for undo functionality). The accelerometer can also be used to control third-party apps, notably games. It is also used for fitness tracking purposes, primarily as a pedometer. Starting with the iPhone 5S, this functionality was included in the M7 Motion coprocessor and subsequent revisions of the embedded chip
Magnetometer A magnetometer is built-in since the iPhone 3GS, which is used to measure the strength and direction of the magnetic field in the vicinity of the device. Sometimes certain devices or radio signals can interfere with the magnetometer requiring users to either move away from the interference or re-calibrate by moving the device in a figure-eight motion. Since the iPhone 3GS, the iPhone also features a Compass app, which was unique at time of release, showing a compass that points in the direction of the magnetic field.
Gyroscopic sensor Since the iPhone 4, the 4th Generation iPod touch, and the iPad 2, a three-axis gyroscope was included. This sensor will run on six axes due to the combination of a gyroscope and an accelerometer. One of the main reasons of the implementation was to enhance gaming mechanics such as the sensitivity and responsiveness aspects. It is compatible with iPhone, iPad, and iPod touch.
Radio Some previous iPhone models contained a chip capable of receiving radio signals; however, Apple has the FM radio feature switched off because there was no antenna connected to the chip. Later iterations of the iPhone (starting with the iPhone 7), however, do not contain radio chips at all. A campaign called "Free Radio On My Phone" was started to encourage cellphone manufacturers such as Apple to enable the radio on the phones they manufacture, reasons cited were that radio drains less power and is useful in an emergency such as the 2016 Fort McMurray Wildfire.
Fingerprint sensor Until 2017, iPhone models starting from iPhone 5S (excluding the iPhone 5C) featured Apple's fingerprint recognition sensor. It is used for unlocking the device and authenticating Apple Pay purchases (since the iPhone 6) using Touch ID. It is located in the home button. Touch ID has been replaced by Face ID (with the exception of the iPhone SE series), starting with the iPhone X. The fingerprint sensor uses the user's biometric information to give the user quick access to the device. It can also be used to open applications and approve transactions. It's compatible with iPhone, iPad, and iPod touch.
Barometer Included on the iPhone 6 and later (excluding the iPhone SE (1st generation)), a barometer is used to determine air pressure and elevation. This sensor is used to provide position and navigational features by determining the altitude through evaluating air pressure. The barometers will allow the device to be pinpointed.
Facial recognition sensor Starting with the iPhone X, a facial recognition sensor, named the TrueDepth camera system, is featured. It is used for unlocking the device and for authenticating purchases using Face ID. It can also be used for Animojis and AR. Now Apple added a feature making it so it checks if you are paying attention, in order to unlock or use Face ID. Also allowing it so you can lock apps with Face ID.
Audio and output
On the bottom of the iPhone, there is a speaker to the left of the dock connector and a microphone to the right. iPhone models from the first-generation to iPhone 4S utilize the 30-pin dock connector, while the models from iPhone 5 to iPhone 14 use the proprietary Lightning connector.
There is an additional loudspeaker above the screen that serves as an earpiece during phone calls. The iPhone 4 includes an additional microphone at the top of the unit for noise cancellation, and switches the placement of the microphone and speaker on the base on the unit—the speaker is on the right. Volume controls are located on the left side of all iPhone models and as a slider in the iPod application.
The 3.5 mm headphone jack was located either on the top left corner or to the bottom left corner of the iPhone. The headphone socket on the first-generation iPhone is recessed into the casing, making it incompatible with most headsets without the use of an adapter. The iPhone 7 and later have no 3.5 mm headphone jack, and instead headsets must connect to the iPhone by Bluetooth, use Apple's Lightning connector, or (for traditional headsets) use the Lightning to 3.5 mm headphone jack adapter. This adapter was included on several models of iPhone, and is also available for purchase at several leading retailers. Beginning with the iPhone 15 series, the Lightning connector was replaced with a USB-C connector, therefore requiring that the headset use the aforementioned connector, or connect via a USB-C to 3.5 mm headphone jack adapter, such as Apple's.
The built-in Bluetooth 2.x+EDR supports wireless earpieces and headphones, which requires the HSP profile. Stereo audio was added in the 3.0 update for hardware that supports A2DP. While non-sanctioned third-party solutions exist, the iPhone does not officially support the OBEX file transfer protocol. The lack of these profiles prevents iPhone users from exchanging multimedia files, such as pictures, music and videos, with other Bluetooth-enabled cell phones.
Mirrored display output is supported via a HDMI adapter, connected to the iPhone Lightning connector.
Battery