Boolean and truth table for circuit

In summary, the conversation discusses a problem involving transistors and how to turn a circuit into a boolean expression. The output for different inputs is also mentioned and the role of transistors in performing gating operations is explained. The conversation ends with a suggestion to consider the current flow and potential differences to find a solution.
  • #1
pyroknife
613
3
I attached the problem statement.

The problems I have done in the past always involved gates (AND, OR, etc...)
Now this involves transistors, I honestly don't know how to go about doing this.

One of the hints for the problem is to assume the ideal transistors are operating in cutoff or saturation.

I don't understand how this circuit can be turned into a boolean expression.
 

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  • #2
pyroknife said:
I attached the problem statement.

The problems I have done in the past always involved gates (AND, OR, etc...)
Now this involves transistors, I honestly don't know how to go about doing this.

One of the hints for the problem is to assume the ideal transistors are operating in cutoff or saturation.

I don't understand how this circuit can be turned into a boolean expression.

If A and B are low, what is the output?

If either A or B are high, what is the output?

Makes sense?
 
  • #3
berkeman said:
If A and B are low, what is the output?

If either A or B are high, what is the output?

Makes sense?

If A and B are low then the output is 0.
If A and B are high then the output is 1.

If A or B are high, the output is 1.

But what do the transistors do for this case?
 
  • #4
pyroknife said:
If A and B are low then the output is 0.
If A and B are high then the output is 1.
If A or B are high, the output is 1.
How did you work out these answers? Do you understand how transistor switches operate? (Not exactly a rhetorical question, though it may appear so.)

But what do the transistors do for this case?
The transistors are the voltage-controlled switches that perform the gating operation. Without them, you don't have logic gates.
 
  • #5
Perhaps the best way to look at the logic is 'what path will the current take when either transistor is enabled. Remember when no current is flowing, the potentials across either side are the resistor are the same. Hope that provide a clue.
 

1. What is a Boolean and truth table for a circuit?

A Boolean and truth table for a circuit is a graphical representation of all possible input combinations and their corresponding outputs in a logic circuit. It shows the logical relationship between inputs and outputs and is used to analyze and design digital circuits.

2. How do you construct a Boolean and truth table for a circuit?

To construct a Boolean and truth table for a circuit, first identify all the inputs and outputs of the circuit. Next, list all possible input combinations in binary form. Then, using the logical operators AND, OR, and NOT, calculate the outputs for each input combination. Finally, organize the inputs and outputs in a table, with inputs listed in columns and outputs listed in rows.

3. What is the difference between a Boolean and truth table and a logic gate diagram?

A Boolean and truth table is a graphical representation of the relationship between inputs and outputs in a logic circuit, while a logic gate diagram is a graphical representation of the physical components (logic gates) used to implement the logical operations in a circuit. A truth table is used for analysis and design, while a logic gate diagram is used to show the physical implementation of a circuit.

4. Why is a Boolean and truth table important in digital circuit design?

A Boolean and truth table is important in digital circuit design because it allows engineers to analyze and understand the behavior of a circuit for all possible input combinations. It also helps to identify errors and optimize the design of the circuit for better performance.

5. Can a Boolean and truth table be used for any type of circuit?

Yes, a Boolean and truth table can be used for any type of circuit that has logical operations. It is commonly used in digital circuits, but can also be used in analog circuits and even in software programming to represent the logical behavior of a program.

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