# Gates & Circuits

## Key Terms

- Analog: Containing values that may take on any continuous value.
- Bistable environment: An electronic setup that requires distinguishing two electric states from each other and maintaining the two separate states.
- Bits: Binary digits; a set of individual binary digits, each of which is 1 or 0.
- Boolean expression: An expression that evaluates to true or false and is constructed from true-false predicates and Boolean operations.
- Boolean logic: A logical system that describes rules for working with two values: true and false.
- Circuit: A collection of gates that together computes something.
- Compare-for-equality circuit (CE circuit): Tests two unsigned binary numbers for exact equality.
- Computing agent: An abstract concept representing any object capable of understanding and executing our instructions.
- Control circuits: Circuits whose purpose is to control the order or choice of what a computer is doing.
- Core: Small, magnetizable, iron oxide-coated “doughnut,” about 1/50 of an inch in inner diameter, with wires strung through its center hole.
- Decoder: A control circuit that turns on one of its outputs when given an input that matches it.
- Gate: An electronic device that operates on a collection of binary inputs to produce a binary output.
- Hardware design: The process of designing circuits and other physical computer systems.
- Magnetic core: A form of memory storage from the past that used small iron disks to generate magnetic fields in response to electric currents.
- Multiplexor: A control circuit that selects one of its input values to pass through to its output, depending on a code passed in along selector lines.
- Sum-of-products algorithm: A process for determining a circuit by starting with its truth table and then generating a Boolean expression for it.
- Transistor: A solid-state electronic device that may or may not let a current through and changes state in response to an electronic control input.
- Truth table: A table showing the truth values of a Boolean expression for every possible combination of inputs.