Last night Walter @wandrson taught a class on the LTSpice (http://www.linear.com/designtools/software/#LTspice) circuit design and analysis tool. We drew up and tested four circuits, including Walter’s “blinking LED” circuit. We analyzed them using the Spice tool, too.
If was a fun class, even if my installation of LTSpice, wouldn’t cooperate until I figured out the symbol/component path had been corrupted.
Walter thank you for the class!
I’ll have to check that one out!
Dan, thank you for the kind words. For those who might be interested I have scheduled another one of these classes Sunday the 27th at 4:00p It should show up on the calendar in 72hours (8/4 @4:10p)
OK without to much rant and rave I managed to get the home ckt entered and simulated.
Ckt is here:https://dallasmakerspace.org/wiki/UsingLTSpicePart1
Here’s the schematic:
Future project: LMxxxx Vreg w/ high current pass transistor. Lays background for a future build.
Cool. Remember, bonus homework points if you also breadboard the circuit and compare the scope output to the simulator output!
Why is the current going the wrong way in a resistor?
LTspice has to pick a reference current direction, and it can only be one way. Think of it like the current convention used in Kirchhoff’s circuit laws. Simply rotate your resistor 180 degrees in the schematic and the current will be to your liking. Alternate: Download File:Res.asy and place in your /lib/sym folder. This symbol has a small arrow indicating the defined way current flows.
Anyone can be an analog circuit designer…
Art, it is time to put down the mouse and pick up a soldering iron! 
Well…just started a simulation w/ pulsed loads. 3 pwrfets w/ load resistors. 1, 4, and 5 A in different combos. Looks like this going to take while…a loooong while. 
Amazon.com has a book titled “The LTSPICE IV Simulator”. Search for ISBN number 9783899292589. Kind of pricey at $45.34 but it is a great hard bound book with the Manual, Methods and Applications in 740 pages. I have a copy and let me know if you want to check it out before you put your money down for your own copy.
thanks just added! dddddddddddddddddddddadsf
