Digital Signals and Gates
While the binary numeration system is an interesting mathematical abstraction, we haven't yet seen its practical application to electronics. This chapter is devoted to just that: practically applying...
View ArticleThe NOT Gate
The single-transistor inverter circuit illustrated earlier is actually too crude to be of practical use as a gate. Real inverter circuits contain more than one transistor to maximize voltage gain (so...
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The "buffer" Gate
If we were to connect two inverter gates together so that the output of one fed into the input of another, the two inversion functions would "cancel" each other out so that there would be no inversion...
View ArticleMultiple-Input Gates
Inverters and buffers exhaust the possibilities for single-input gate circuits. What more can be done with a single logic signal but to buffer it or invert it? To explore more logic gate possibilities,...
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TTL NAND and AND Gates
Suppose we altered our basic open-collector inverter circuit, adding a second input terminal just like the first: This schematic illustrates a real circuit, but it isn't called a "two-input...
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TTL NOR and OR Gates
Let's examine the following TTL circuit and analyze its operation: Transistors Q1 and Q2 are both arranged in the same manner that we've seen for transistor Q1 in all the other TTL circuits. Rather...
View ArticleCMOS Gate Circuitry
Up until this point, our analysis of transistor logic circuits has been limited to the TTL design paradigm, whereby bipolar transistors are used, and the general strategy of floating inputs being...
View ArticleSpecial-Output Gates
It is sometimes desirable to have a logic gate that provides both inverted and non-inverted outputs. For example, a single-input gate that is both a buffer and an inverter, with a separate output...
View ArticleGate Universality
NAND and NOR gates possess a special property: they are universal. That is, given enough gates, either type of gate is able to mimic the operation of any other gate type. For example, it is possible to...
View ArticleLogic Signal Voltage Levels
Logic gate circuits are designed to input and output only two types of signals: "high" (1) and "low" (0), as represented by a variable voltage: full power supply voltage for a "high" state and zero...
View ArticleDIP Gate Packaging
Digital logic gate circuits are manufactured as integrated circuits: all the constituent transistors and resistors built on a single piece of semiconductor material. The engineer, technician, or...
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