74AS00 Quad 2-Input NAND Gate. Physical Dimensions inches (millimeters) unless otherwise noted (Continued). Lead Plastic Dual-In-Line Package ( PDIP). 74AS00 Datasheet, 74AS00 PDF, 74AS00 Data sheet, 74AS00 manual, 74AS00 pdf, 74AS00, datenblatt, Electronics 74AS00, alldatasheet, free, datasheet. description. These devices contain four independent 2-input positive-NAND gates. They perform the Boolean functions Y = A • B or Y = A + B in positive logic.
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Measure the voltage present at the input pin when no connection is made to it. What is the meaning of hysteresis? Why is negative logic commonly used? What is the range that would be considered a logic HI? Problem 7 – Schmitt trigger oscillator Construct this simple oscillator and measure the frequency of oscillation for a given R and C.
Open-Collector Output Figure 6. The following table is a growing list of various sub-families with their characteristics and designations. What is meant by tri-state or 3-state outputs? This is called the high impedance or Hi-Z state. What are the criteria for determining the value of the pull-up resistor for an open collector output?
The propagation delay inherent in gates can be useful for creating oscillatory circuits. 74ws00 simulation and debugging is conducted on the computer before the chip is created.
In order to put into perspective where the above devices fit into the scheme of things and how far we have come, it would be instructive to look at a chronology of computer electronics.
Draw the input and output waveforms timing diagram.
Families can be characterized by the relationship between propagation-delay and power. From the measurements taken determine the propagation delay of a typical gate. Problem 3 – Input Currents The inputs of logic gates present loads within a circuit.
Two important factors in the consideration of each logic family are speed and power consumption. What is the difference between open collector, tri-state and totem-pole outputs? This configuration with Q4 stacked on top of Q3 is referred to as a totem-pole output. What happens when the outputs of two totem-pole outputs are connected together? This is useful for creating a party-line data bus or control bus whereby any one of several circuits may pull the line LO without causing damage to another active output.
Problem 10 What is meant by negative logic? An open-collector output has current sinking capabilities, that is, it can present a logic-LO output. To present basic characteristic and limitations of gates.
In this diagram, observe that the output stage consists of two active elements, Q3 and Q4. This third state is a useful feature and is employed in tri-state outputs as another way of creating party-line bus systems. Also shown in Figure 6. Analyze the circuits and explain the results. What is the minimum and maximum values of R and C? Use a 1K potentiometer to supply a variable input voltage.
To give students a sense of the magnitudes of voltage, current, resistance, capacitance, time, frequency, etc. The voltage at the output pin is indeterminate and is said to be floating. What is the input hysteresis in volts for these two gates? Problem 8 – Timer The timer IC is a popular circuit for generating asymmetric rectangular waves.
Observe here that the circuit elements associated with Q4 in the totem-pole circuit are missing and the collector of Q3 is left open-circuited, hence the name open-collector.
Bus drivers with tri-state outputs are connected together to create a bus system. Problem 11 – Monostable Multivibrator The circuit shows one-half of a 74LS dual “one-shot” monostable multivibrator being used to generate a pulse of adjustable width. Construct and test this circuit.