Flight attendant. Flight attendants or cabin crew (also known as stewards/stewardesses, air hosts/hostesses, cabin attendants) are members of an aircrew employed by airlines primarily to ensure the safety and comfort of passengers aboard commercial flights, on select business jet aircraft, and on some military aircraft.
Half adder circuit. To understand what is a half adder you need to know what is an adder first. Adder circuit is a combinational digital circuit that is used for adding two numbers. A typical adder circuit produces a sum bit (denoted by S) and a carry bit (denoted by C) as the output.
Simply put, an encoder is a sensing device that provides feedback. Encoders convert motion to an electrical signal that can be read by some type of control device in a motion control system, such as a counter or PLC. The encoder sends a feedback signal that can be used to determine position, count, speed, or direction.