Wonderful! I did sh!t like this when I was a kid, trying to figure out how things "electronical" worked. Of course, way back then, I didn't have a personal computer with a sound card to play with. No one did, because they hadn't been invented yet. So, one of the very first pieces of test gear I bought with money earned from my newspaper route was a Heathkit variable frequency oscillator. That was right after I purchased a kit Vacuum Tube Volt Meter (VTVM) made by RCA. Can't do any experiments without measurements, right?
Well, that kept me busy for awhile, but I soon realized that what I really needed was an oscilloscope, because once you introduce capacitors and inductors into your experimental circuits, phase becomes important. Ahem. About the only thing I knew about phase was gleaned from books I borrowed from the library, so further experiments didn't happen overnight. I was almost ready to graduate high school before I had saved enough money purchase a kit EICO 460K oscilloscope, about 1961.
I never did any experiments with homemade parallel plate capacitors, with or without a pancake inductor between the plates, although I did construct a high-voltage parallel plate capacitor using aluminum foil, rubber cement, and window glass. This was supposed to be the resonating capacitor for the primary of a Tesla coil, but I was stymied by my inability to wind the secondary. And I had no means to measure the resonant frequency of the primary, although much later I did acquire a Heathkit grid-dip meter that would have measured to within a few kilohertz... probably gud enuf fer amatoor werk.
So fast forward past high school graduation, the Viet Nam war, ten years of part-time study ending in a BEE degree in 1978 and I was ready to face the world with a
bona fide engineering degree. I spent the next thirty-something years working as an electrical engineer for companies with United States Government contracts, usually something for the Department of Defense or Homeland Security. I retired to Florida in December 2016 and have been looking for something to do ever since... maybe some projects employing Microchip PIC microprocessors.
My latest idea is a toilet seat alarm, to remind men to put the seat down for women in their house. Seems like this simple task of lowering the toilet seat is abhorrent to most women. Germs, perhaps? I have installed self-lowering toilet seats that lower gently instead of with a bang, but wife says that's not good enough. I have to be responsible for seeing that the seat is down before she needs to use it. Hence the need for some sort of reminder that the seat is still up before I exit the bathroom. Urinating from a standing position over a lowered toilet seat is NOT an option, no matter how good my aim might be.
So, I bought a bunch of ball-in-cylinder tilt switches, made in China of course, from Amazon. Advertisement blurb says they are intended to interface with Arduino Uno microcontrollers. Well, they are simple on/off switches... why wouldn't they interface with an Arduino input port?
Problem is, these switches are very sensitive to an exact vertical orientation before the switch will close. Not that easy to get installed correctly on the bottom of the toilet seat. Plus, I need some way to know that the toilet seat is raised and someone is present (or not) before sounding an alarm.
This contraption must be battery powered, perhaps with a pair of AA NiMH rechargeable cells. And it needs an audible alarm (like smoke detectors have) to signal when the battery voltage is low, and an alarm to signal when the toilet seat is left up and no one is nearby to lower it. But this latter alarm must also be triggered if the seat is up and someone approaches the seat. And it should turn itself off for awhile, to save battery energy, if the "seat up" condition isn't corrected within a certain time interval.
Lots of design decisions to consider before actually soldering anything together. Plus I need to search the Internet because someone has probably already solved this "problem" cheaper, better, and simpler than whatever I might come up with. I am thinking a magnet and a magnetic reed switch might be a better seat-position sensor than a ball-in-cylinder tilt switch... some experiments are necessary.
So, my advice to
@epsolutions is to get some test equipment together and start building your experiment. Keep careful notes of your setups, the voltages and/or currents you measure, and what you think it all means. Make sure your results are reproducible by others "skilled in the art" as well as, later, by yourself.
By all means, obtain a modern digital storage oscilloscope to allow you to make simultaneous measurements of wave forms in two or more circuit locations. A good sinusoidal oscillator is recommended for the kind of experiments you want to do. I recommend that you purchase or build a Wien Bridge oscillator for this purpose. If your experiments wander into the realm of radio frequencies, a stable RF oscillator would be necessary.
Good luck in your retirement! And always remember that electronics is supposed to be FUN!
Hop -- AC8NS