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.
1. SCR: Silicon Controlled Rectifier. A semiconductor device that functions as an electrically controlled switch. (a) An SCR is one in the family of semiconductors that includes transistors and diodes. (b) The basic purpose of a SCR is to function as a switch that can turn on or off small or large amounts of power.