Combinational Logic
Digital-to-Analogue Converters, or DAC’s as they are more commonly known, are the opposite of the Analogue-to-Digital Converters we looked at in a previous tutorial. DAC’s convert binary or non-binary numbers and codes into analogue ones with its output voltage (or current) being proportional to the value of its digital input number. For…
We saw in the previous tutorial about the binary weighted digital-to-analogue converter that the analogue output voltage is the weighted sum of the individual inputs, and that it requires a large range of precision resistors within its ladder network, making its design both expensive and impractical for most DAC’s requiring lower levels…
Analogue-to-Digital Converters, (ADCs) allow micro-processor controlled circuits, Arduinos, Raspberry Pi, and other such digital logic circuits to communicate with the real world. In the real world, analogue signals have continuously changing values which come from various sources and sensors which can measure sound, light, temperature or movement, and many digital…
The analogue switch is a solid-state semiconductor switch that controls the transmission path of analogue signals. The open and closed operations of the switch positions are usually controlled by some digital logic network, with standard analogue switches available in many styles and configurations. For example, single or dual normally open…
Another common and very useful combinational logic circuit which can be constructed using just a few basic logic gates allowing it to add together two or more binary numbers is the Binary Adder. A basic Binary Adder circuit can be made from standard AND and Ex-OR gates allowing us to “add” together two single bit…
A Transceiver can be used to provide bidirectional, input or output control, of either digital or analogue devices to a common shared data bus. Unlike the buffer, transceivers are bidirectional devices which allow data to flow through them in either direction. Thus their name “transceiver” is a portmanteau word coming from the…
Digital or Binary Comparators are made up from standard AND, NOR and NOT gates that compare the digital signals present at their input terminals and produce an output depending upon the condition of those inputs. For example, along with being able to add and subtract binary numbers we need to be able to compare them…
As their name implies, a Binary Subtractor is a decision making circuit that subtracts two binary numbers from each other, for example, X – Y to find the resulting difference between the two numbers. Unlike the Binary Adder which produces a SUM and a CARRY bit when two binary numbers are added together, the binary subtractor produces a…
A Digital Decoder IC, is a device which converts one digital format into another and one of the most commonly used devices for doing this is called the Binary Coded Decimal (BCD) to 7-Segment Display Decoder. 7-segment LED (Light Emitting Diode) or LCD (Liquid Crystal Display) type displays, provide a very convenient way of displaying information…
Unlike a multiplexer that selects one individual data input line and then sends that data to a single output line or switch, Digital Encoder more commonly called a Binary Encoder takes ALL its data inputs one at a time and then converts them into a single encoded output. So we can say that a…
The name “Decoder” means to translate or decode coded information from one format into another, so a binary decoder transforms “n” binary input signals into an equivalent code using 2n outputs. Binary Decoders are another type of digital logic device that has inputs of 2-bit, 3-bit or 4-bit codes depending upon the…
Multiplexing is the generic term used to describe the operation of sending one or more analogue or digital signals over a common transmission line at different times or speeds and as such, the device we use to do just that is called a Multiplexer. The multiplexer, shortened to “MUX” or “MPX”, is…