DE: Activity 1.1.6 Digital Component Identification

DE: Activity 1.1.6 Digital Component Identification

In this activity, you will investigate both combinational and sequential logic gates. You will be asked to simulate simple circuits using basic logic gates. You will then complete a truth table for each logic gate based on the outputs generated from your simulation. The names of many of the fundamental logic gates in digital electronics are based on the logic output from the gate. From the analysis of a truth table, could you determine the name and understand the function of the gate?

You will examine the basic building block of sequential logic: the flip-flop. The investigation will conclude with a look at the 555 IC and how it is used to trigger events in a circuit.

Open Ended

Describe the structure of a truth table and how to “count in binary”. (possible input combinations)

Open Ended

This lesson discusses transistors, logic gates, integrated circuits (ICs). Explain the relationship of each.

Open Ended

Describe the TTL logic gate numbering system.

Open Ended

Define the scale of integration and package styles.

In this activity, you will investigate both combinational and sequential logic gates. You will be asked to simulate simple circuits using basic logic gates. You will then complete a truth table for each logic gate based on the outputs generated from your simulation. The names of many of the fundamental logic gates in digital electronics are based on the logic output from the gate. From the analysis of a truth table, could you determine the name and understand the function of the gate?

You will examine the basic building block of sequential logic: the flip-flop. The investigation will conclude with a look at the 555 IC and how it is used to trigger events in a circuit.

Using the Circuit Design Software (CDS), create the circuit for each logic gate shown.

Note: In each of the circuits, an input of 0 occurs when the switch is at GND. An input of 1 occurs when the switch is at +5V. Likewise, when the output probe is on, the output is a 1. When the output probe is off, the output is a 0.

Open Ended

From the analysis of the truth table, why do you think this is called an “INVERTER” gate?

Open Ended

From the analysis of the truth table, why do you think this is called an “AND” gate?

Open Ended

From the analysis of the truth table, why do you think this is called a “NAND” gate? (NOT AND)

Open Ended

From the analysis of the truth table, why do you think this is called an “OR” gate?

Open Ended

From the analysis of the truth table, why do you think this is called a “NOR” gate? (NOT OR)

Combinational Logic

Digital circuitry in which an output is derived from the combination of inputs, independent of the order in which they are applied.

Sequential Logic

Digital circuitry in which the output state of the circuit depends not only on the states of the inputs, but also on the sequence in which they reached their present states.

Open Ended

Open Ended

Later in this course, we will learn how to combine flip-flops to make transitions to desired outputs. The flip-flop is holding a bit of information, waiting for a signal to change (memory). But in this example, you are making the transition by flipping a switch.

How can we make the flip-flop change without us providing the input directly?

Open Ended

Open Ended

Can you combine the 555 Timer circuit with the flip-flop circuit so the changes on the flip-flop happen without your input at a rate you desire? Share this simulation with your instructor.