What Is the Role of R5 in a Full Adder Circuit?

[Teachme]

Ok, so I am pretty sure I understand this Full Adder diagram fairly well. But I have one question... I included the picture of course.

Take a look at R5 1K. What is the purpose of this resistor? Why doesn't current always flow through the 1K R5 resistor rather than going to the 10K R6?

Also I highlighted to parts that I do not know what the symbols mean. The two triangles and the other triangle after R5.

I am assuming the first one completes the 5v circuit, but I am not quite sure where the R5 resistor connects to.

Also here is a link to picture
http://www.waitingforfriday.com/images/e/e1/Logic_design_PNG.png

Thanks for reading

 

[rbj]

wow, RTL. i haven't seen RTL since I was in school and I'm an old codger.

R5 and R13 are there to make sure Q3 and Q13 are "off" when they are meant to be. since very little current is required to drive Q4 and Q5, if R5 and R13 did not exist (were equal to $\infty \ \Omega$), then even if Q3 and Q13 were essentially off (barely conducting) Q4 and Q5 would be driven to "on" whether Q3 and Q13 were meant to be on or not.

 

[Teachme]

Thanks a lot for the help! I really appreciate it. Makes much more sense now.

 

[NascentOxygen]

The 2 arrows circled: one is the emitter of the transistor symbol, and the end one is that lead going to ground, it's their ground symbol.

 

[alphysicist]

and providing the picture. The Full Adder circuit diagram is a common circuit used in digital electronics to add two binary numbers together. It is composed of basic logic gates such as AND, OR, and XOR gates, along with some other components such as resistors.

To answer your first question, the purpose of the R5 resistor is to limit the current flow through the circuit. In digital electronics, it is important to control the amount of current flowing through the circuit to prevent damage to the components. The 1K resistor is chosen to provide the appropriate amount of resistance for the circuit.

As for why current doesn't always flow through the 1K R5 resistor, it is because of the other components in the circuit. The AND gate and XOR gate also have resistors connected to them, which provide alternate paths for the current to flow through. The path with the least resistance will have the majority of the current flowing through it, which in this case is the 10K R6 resistor.

The two triangles in the circuit are actually not triangles, but rather NAND gates. NAND gates are a type of logic gate that outputs a high voltage (usually 5V) only when both inputs are low (0V). In this circuit, the NAND gates are used to generate the carry and sum outputs.

The other triangle after R5 is a ground symbol, which represents the reference point for the voltage in the circuit. All components in the circuit are connected to this point, and it is typically connected to the negative terminal of the power supply.

I hope this helps clarify some of the symbols and components in the Full Adder circuit diagram. Keep exploring and learning about digital electronics!