📚 Input and Output Devices | 输入与输出设备
Input and output devices form the boundary between an information-processing system and the outside world. In Cambridge IGCSE Science and ICT, an input device converts a physical quantity or a user action into electrical signals, while an output device converts processed signals back into a form humans can sense or into an action that changes the environment. Understanding these devices helps students choose the right tools for data collection, measurement, display, and control.
输入设备和输出设备构成信息处理系统与外部世界之间的边界。在剑桥 IGCSE 科学和 ICT 中，输入设备将物理量或用户操作转换为电信号，而输出设备将处理后的信号转换回人类可以感知的形式，或转换为改变环境的动作。理解这些设备有助于学生选择正确的工具进行数据采集、测量、显示和控制。
1. What Is an Input Device? | 什么是输入设备？
An input device is any hardware component that sends data or signals to a processing unit. The data may come from a human user, such as typing on a keyboard, or from the environment, such as a temperature sensor detecting heat. The device must convert the input into an electrical form because processors work with voltages and digital logic.
输入设备是向处理单元发送数据或信号的任何硬件组件。数据可以来自人类用户，例如在键盘上打字，也可以来自环境，例如温度传感器检测热量。输入设备必须将输入转换为电信号形式，因为处理器工作依赖于电压和数字逻辑。
In science, input devices are often sensors. A thermistor changes its resistance with temperature, so the voltage across it changes. A light-dependent resistor (LDR) does the same for light intensity. These changing voltages are sampled and turned into digital values by an analogue-to-digital converter (ADC).
在科学中，输入设备通常是传感器。热敏电阻的电阻随温度变化，因此其两端的电压也变化。光敏电阻（LDR）对光照强度有类似的响应。这些变化的电压被采样，并由模数转换器（ADC）转换为数字值。
2. What Is an Output Device? | 什么是输出设备？
An output device receives processed data from the system and presents it to the user or environment. Examples include monitors, printers, speakers, and projectors. The output can be visual, audible, printed, or physical movement.
输出设备接收系统处理后的数据，并将其呈现给用户或环境。例子包括显示器、打印机、扬声器和投影仪。输出可以是视觉、听觉、打印或物理运动。
In a control experiment, an output device may be an actuator. For example, a relay can switch on a heater when the temperature falls below a set point. In this way, the output does not just display a result; it actively changes the system being studied.
在控制实验中，输出设备可以是执行器。例如，当温度低于设定值时，继电器可以打开加热器。这样，输出不仅仅显示结果，还主动改变所研究的系统。
3. Manual Input Devices: Keyboard and Mouse | 手动输入设备：键盘与鼠标
A keyboard is a manual input device because it requires the user to press keys. Each key press is converted into a unique code that the computer interprets as a letter, number, or command. This is essential for entering experimental labels, units, and observation notes.
键盘是一种手动输入设备，因为它需要用户按键。每次按键都会转换为唯一的代码，计算机将其解释为字母、数字或命令。这对于输入实验标签、单位和观察记录是必不可少的。
A mouse is another manual input device. An optical mouse uses an LED or laser and a camera sensor to detect movement across a surface. Buttons allow the user to select, drag, and open objects. In data analysis software, the mouse selects points on a graph or adjusts the scale.
鼠标是另一种手动输入设备。光电鼠标利用 LED 或激光以及相机传感器检测表面上的移动。按钮允许用户选择、拖动和打开对象。在数据分析软件中，鼠标可以选择图形上的点或调整刻度。
4. Automatic Input Devices: Sensors | 自动输入设备：传感器
Automatic input devices collect data without constant human operation. Sensors respond to physical changes and produce an electrical signal. A temperature sensor may use a thermocouple or thermistor, while a light sensor often uses a photodiode or LDR.
自动输入设备无需持续人工操作即可采集数据。传感器对物理变化作出响应并产生电信号。温度传感器可以使用热电偶或热敏电阻，而光传感器通常使用光电二极管或光敏电阻。
Common science sensors include pH probes, pressure sensors, motion sensors, and oxygen sensors. These allow continuous monitoring of reactions, ecosystems, or weather. Automatic data collection reduces human reaction time and transcription errors, and it can operate in hazardous environments.
常见的科学传感器包括 pH 探头、压力传感器、运动传感器和氧气传感器。它们可以连续监测化学反应、生态系统或天气。自动数据采集减少了人为反应时间和记录错误，并且可以在危险环境中工作。
5. Scanning and Imaging Inputs | 扫描与成像输入
Scanners convert printed images and text into digital form. A flatbed scanner moves a light source and sensor along a document, recording reflected light as pixels. This allows reports, graphs, and field sketches to be stored and edited.
扫描仪将印刷图像和文本转换为数字形式。平板扫描仪沿文档移动光源和传感器，将反射光记录为像素。这使得报告、图表和野外草图可以被存储和编辑。
Digital cameras and microscope cameras are also input devices. They capture light through a lens and convert it into an image file. In biology, a digital microscope records cell structures, which can then be measured on screen. Barcode readers use reflected laser light to enter sample codes quickly.
数码相机和显微镜相机也是输入设备。它们通过镜头捕捉光线并将其转换为图像文件。在生物学中，数字显微镜记录细胞结构，然后可以在屏幕上测量。条形码阅读器利用反射激光快速输入样品代码。
6. Display Output Devices: Monitors and Projectors | 显示输出设备：显示器与投影仪
A monitor displays text, images, and live graphs. Modern monitors use liquid crystal display (LCD) or organic light-emitting diode (OLED) technology. Each pixel is controlled electronically to produce colours and brightness levels.
显示器显示文字、图像和实时图形。现代显示器使用液晶显示（LCD）或有机发光二极管（OLED）技术。每个像素都由电子控制，以产生颜色和亮度级别。
gives sharper detail. Projectors work like monitors but project a larger image onto a wall or screen. They are useful for classroom demonstrations and group analysis.
屏幕分辨率是水平和垂直方向的像素数量，例如 1920 × 1080。分辨率越高，细节越清晰。投影仪类似于显示器，但将较大的图像投射到墙壁或屏幕上。它们适用于课堂演示和小组分析。
7. Printers and Plotters |
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