Fig. 1-10 Digital inverter. (a) Model. (b) Truth table. (c) Symbol. (d) Another symbol.
Negation given in Fig. 1-10b. Clearly the output is the negative, or the inverse, of the input.
Tri- state inverter When the inverter is used as a logic circuit, H is often defined as the ‘’true’’ state, while L is defined as the ‘’false’’ state In this state ,the inverter will always provide at its output a signal that is the inverter. Or complement, of the signal at input. It is thus called a negation or NOT circuit. This makes sense, since there are only two possible states, and therefore NOT H must be L and must be H.
The inverse or complement of a signal is shown by writing a bar above the symbol. For instance , the complement of A is written as ¯A ,and this is read as ‘’ A bar.’’ A logic expression for the inverter in Fig. 1-10c is V0 =V ̅i. It is read ‘’V sub oh is equal to V sub eye bar.’’
The standard symbol for an inverter is given in Fig. 1-10c. Notice the small circle (bubble) at the output. This small circle signifies inversion, and it is used on many other logic symbols. For instance, the symbol in Fig. 1-10d has the small circle on the input side. This is still an inverter, but the circle on the input side has additional significance. which will be considered next. In the standard TTL logic family, a 5404 or7404 s a 14-pin IC with six inverters.
THE TRI –STATE INVERTER
A tri-sate inverter is easy to construct, as shown in Fig. 1-11a. The truth table in Fig. 1-11b shows that when G is low, the inverter is connected to output. When G is high the enable switch open, and the output is disconnected from the inverter. The standard logic symbol for this tri-state inverter s giver in Fig. 1-11c. The inverting amplifier Symbol indicates that V0 is the inverse of Vi (the small circle is at the amplifier output). However, note small circle at the input of the amplifier used for G. From the truth
Fig. 1-10 Digital inverter. (a) Model. (b) Truth table. (c) Symbol. (d) Another symbol.Negation given in Fig. 1-10b. Clearly the output is the negative, or the inverse, of the input.Tri- state inverter When the inverter is used as a logic circuit, H is often defined as the ‘’true’’ state, while L is defined as the ‘’false’’ state In this state ,the inverter will always provide at its output a signal that is the inverter. Or complement, of the signal at input. It is thus called a negation or NOT circuit. This makes sense, since there are only two possible states, and therefore NOT H must be L and must be H. The inverse or complement of a signal is shown by writing a bar above the symbol. For instance , the complement of A is written as ¯A ,and this is read as ‘’ A bar.’’ A logic expression for the inverter in Fig. 1-10c is V0 =V ̅i. It is read ‘’V sub oh is equal to V sub eye bar.’’The standard symbol for an inverter is given in Fig. 1-10c. Notice the small circle (bubble) at the output. This small circle signifies inversion, and it is used on many other logic symbols. For instance, the symbol in Fig. 1-10d has the small circle on the input side. This is still an inverter, but the circle on the input side has additional significance. which will be considered next. In the standard TTL logic family, a 5404 or7404 s a 14-pin IC with six inverters.THE TRI –STATE INVERTERA tri-sate inverter is easy to construct, as shown in Fig. 1-11a. The truth table in Fig. 1-11b shows that when G is low, the inverter is connected to output. When G is high the enable switch open, and the output is disconnected from the inverter. The standard logic symbol for this tri-state inverter s giver in Fig. 1-11c. The inverting amplifier Symbol indicates that V0 is the inverse of Vi (the small circle is at the amplifier output). However, note small circle at the input of the amplifier used for G. From the truth
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