Series Resistor Circuit Voltage (2 Power Sources)

[Jeev]

LTSpice. It's free and great for checking circuits like this.

http://www.linear.com/designtools/software/#LTspice

 

[Mickey]

LTSpice. It's free and great for checking circuits like this.

http://ltspice.linear-tech.com/software/LTspiceIV.exe

My chromebox won't run it, can someone run it and see what it does?

 

[Jeev]

It's circuit simulation software. I used to use this back in uni to quickly check things once my brain had stopped working.

EDIT: Sorry, I won't post the .exe link.

http://www.linear.com/designtools/software/#LTspice

 

[daba]

Here it is....

I don't know how to annotate it but V(n001) is point B in the circuit

 

[Jeev]

I didn't want to post the answer and hurt feelings

 

[daba]

I didn't want to post the answer and hurt feelings

whose ??

 

[Jeev]

whose ??

I jest. Jokes aside, even LTSpice as a scaled down program allows you to do some good diagnostics. The scoping and transient analysis was always useful. I've forgotten how to use it, but the Tranfer Function stuff was helpful at times as well.

 

[Mickey]

GREAT!!

Thanks

 

[daba]

I jest. Jokes aside, even LTSpice as a scaled down program allows you to do some pretty good diagnostics. The scoping and transient analysis was always pretty good. I've forgotten how to use it, but the Tranfer Function stuff was helpful at times as well.

First time I've even seen it, but it looks useful. I downloaded and installed it and managed to build that network, in a couple of minutes, and ran the simulation. I was happy to see it agreed with my manual calculations.

I don't think it would help with digital circuits, such as my 8x8x8 RGB LED Cube project, as that is all multiplexed, but for analog circuits it could be a great tool.

 

[Jeev]

Have a poke around in here: http://www.electronics-lab.com/downloads/

There are a few different circuit simulation tools, and some of them are for Digital.

 

[ebolbol]

Here it is....

I don't know how to annotate it but V(n001) is point B in the circuit

How do you get the operating points window to pop up like in your image?

 

[Jeev]

How do you get the operating points window to pop up like in your image?

You need to "Run" the simulation. The first time you run it; it will prompt you for the simulation type. For this exercise you can pick "DC op pnt" from the Edit Simulation Command prompt.

Also, it will tell you all the node and point names when you mouse-over them.

Google and YT get hits on LTSpice tutorial, and there are many example circuits varying from basic to advanced.

 

[ebolbol]

You need to "Run" the simulation. The first time you run it; it will prompt you for the simulation type. For this exercise you can pick "DC op pnt" from the Edit Simulation Command prompt.

Also, it will tell you all the node and point names when you mouse-over them.

Google and YT get hits on LTSpice tutorial, and there are many example circuits varying from basic to advanced.

I will try that! Thanks so much Jeev and every one else who chimed in to help.

 

[ebolbol]

First time I've even seen it, but it looks useful. I downloaded and installed it and managed to build that network, in a couple of minutes, and ran the simulation. I was happy to see it agreed with my manual calculations.

I don't think it would help with digital circuits, such as my 8x8x8 RGB LED Cube project, as that is all multiplexed, but for analog circuits it could be a great tool.

That's a nifty little setup. How are the patterns controlled?

 

[AustralIan]

I like to use Kirchhoff's current law and Kirchhoff's voltage law.

KCL: the sum of currents flowing into a point in the circuit must be equal to zero.

KVL: The sum of voltage changes in a loop must be equal to zero.

As there are no break-away points, KCL is easy. There is one current, and we will call it 'i' and we will assume it is the current flowing in a clockwise manner.

if you then start at any point in the loop and add up all the voltage changes you get (in my case starting in the lower left hand corner and moving in a clockwise manner).
9 - (47k * i) - (27k * i) - (56k * i) - (20k * i) - 12 = 0

and if we stopped half way with voltage summation:
9 - (47k * i) - (27k * i) = Vb

You now have two equations with two variables, which can be solved for Vb and i. Of note, i is a negative number as current is flowing anticlockwise in this case, not clockwise like in my definition.