Electro-mechanical counting devices are those counting devices that could be operated both electrically and mechanically
These includes the following
Blaise Pascal Machine
Gottfried Leibniz Machine
Joseph Jacquard Loom
Charles Babbage Analytical Engine
OUTPUT DEVICES: There are the physical components of a computer used to obtain results from computer after processing. There devices convert data from machine-readable format into human-readable format.
(a) Monitor (b) Printer (c) Plotter (d) Speaker (e) Projector (f) Microfilm, etc.
KEYS ON KEYBOARD
A keyboard is an input device that resemble a typewriter, which is used to type text, numbers, symbols, commands and to give instructions to the computer.
Alphanumeric keys: These are used to type letters and numbers, the letters A – Z, a – z and the digital 0 – 9.
An input device is a peripheral (piece of computer hardware equipment) used to provide data and control signals to an information processing system such as a computer or information appliance. Examples of input devices include keyboard, mouse, scanners, digital cameras and joysticks, etc.