Download your free LTSpice digital breadboard and have some fun learning electronics. Test and understand your ideas before you actually build something.
Combine LTSpice with a few good electronics texts and you have a wonderful learning environment. You can try all sorts of circuits and experiments in a risk free setting and learn how they work.
Have you ever wondered about a linear regulated power supply? With your LTSpice digital breadboard, you can quickly draw a circuit schematic and see how it works. Most hams are self-taught and LTSpice fits right into this context.
As with most efforts, you learn by doing. The Help file is pretty reasonable. You will find a ton of information in the Internet about SPICE simulators in general, and the LTSpice implementation in particular. There are really two aspects to learning LTSpice. The first aspect is drawing a circuit schematic which is done through a largely visual GUI. Just drop your circuit components onto a canvas and wire them up. One thing you need to remember is judicious placement of grounds to complete network loops and ensure that a matrix of equations can be solved.
The second aspect is choosing the type of analysis you want. AC analysis is the most fun for hams as you can plot circuit performance over a range of frequencies. This means examining performance in the frequency domain. Clicking on a spot in the schematic brings up measurements of voltages, currents, impedance and even power across the spectrum.
The second most used simulation mode is Transient or time domain Analysis. It’s like an oscilloscope. Above, you can see transformer output (red), rectified voltage smoothed with a capacitor (blue) and voltage regulator output (green) over the first 60 milliseconds.
LTSpice Digital Breadboard Power Supply
As shown above, I “built” a simple 5VDC power supply in a few minutes. A voltage source simulates the power mains, and a step-down transformer gets us to 13 volts. Then a rectifier bridge and capacitor provides input into a voltage regulator and, voila, a five volt power supply. With this simple circuit you can learn how to:
- Combine two inductors into a transformers with the right turns ratio
- Wire in diodes as rectifiers
- Experiment with different values of smoothing or filter capacitor, and
- Bias a variable voltage regulator
Having a textbook handy is always good, as you often wonder things like “why is that happening or not”, or how to select component values. While the ARRL Handbook is useful, an intermediate level electrical engineering circuits text is even better, if you can handle a bit of calculus. Here’s a link to the one I use, which I picked up at a used book sale for 25¢ forty years ago.