Has anyone made resistors, cap's, experiments from the start of electrical era ? - Page 1
Forum section: electronics / general

author: lordvader88
author_rank: Frequent Contributor
timestamp: July 14, 2018, 10:25:01 pm
content: I love documentaries/lectures on the history of electricity, there's not enough. A few people might do some old experiments in physics class, or at home.What about trying to make components the way they did at the start ? I'd like to take some clay and charcoal and see if I could make a resistor and bake it or fire it. Would that work ?I made little motors as a kid, but haven't tried any old experiments since I got back into this hobby.What have you folks done ?

author: CopperCone
author_rank: Super Contributor
timestamp: July 14, 2018, 10:34:33 pm
content: One of the most fascinating historical experiments I have found is the experimentation that was done with terahertz radiation and dielectric lens back in 1900 or so. Or maybe it was 1890.Before I get accused of smoking crack,https://www.cv.nrao.edu/~demerson/bose/bose.html

author: chris_leyson
author_rank: Super Contributor
timestamp: July 14, 2018, 10:54:13 pm
content: I had to make a 2 Ohm resistor and a 20pF and maybe an inductor for college a long time ago. The resistor was wire wound on a piece of flat card and the winding direction reversed half way through so as not to be inductive and the 20pF cap was behive trimmer made from odd bits of aluminium and an M3 bolt. Tried making a crystal detector with some wire and carborundum, it didn't work. Woulndn't mind having a go at a Marconic magnetic detector one day.

author: innkeeper
author_rank: Unknown
timestamp: July 15, 2018, 01:40:09 am
content: wow, that brings back memories. our high school had an electronics program, with equipment mostly donated by us military.old dumot oscilliscopes, and these very old Wheatstone bridges that should have been in a museum even back then, beautiful piece of gear in wood boxes.anyway, we had to make our own precision resistors on formers with nichrome wire to make our own meters with using the whetstone bridge, using surplus gruen meters still in the wax and cloth coated boxes. and for replacing those resistors people ultimately burned out in the Simpson 260'simagine my shock when i got to college and they had scopes that were actually calibrated and digital meters....to this day, i still think its hard to beat the accuracy of those Wheatstone bridges. noting like having accuracy down to .001 ohm.. just works of art too.

author: John B
author_rank: Frequent Contributor
timestamp: July 15, 2018, 04:24:33 am
content: DIY is one of the easiest way to experiment with high voltage capacitors, all you need is aluminium foil and a thick plastic sheet, like ~1.5mm acrylic or similar. It's not very difficult to get 10nF and >20kV (except for all the elbow grease in charging it up). Don't touch it!

author: CatalinaWOW
author_rank: Super Contributor
timestamp: July 15, 2018, 05:08:34 am
content: Tube circuits are high impedance. Made for large resistances and relatively small capacitances. Resistors can be made fairly well with paper, soft pencil and a couple of alligator clips. Small caps stacked with Mica (or nowdays with plastic wrap) and foil are also easy.But just like those electric motors you made, they aren't really suitable for long term use. That is much tougher, but still well within home fab capability as long as you accept low yield and lots of selection/sorting to get the right values.

author: German_EE
author_rank: Super Contributor
timestamp: July 15, 2018, 11:44:51 am
content: In the 1980's a design for an automatic antenna tuner was published, a unit called the PICATUNE designed by G3XJP. The capacitors in the tuner need to be high voltage and high Q so the builder is expected to make their own using polythene from freezer bags, silicone grease and copper or brass foil.It works, but it's very messy.http://www.carnut.info/picatune.htm

author: bd139
author_rank: Super Contributor
timestamp: July 15, 2018, 11:50:10 am
content: I built my own electrolytic capacitors when I was a kid. Kitchen roll, carrier bags, tin foil and various electrolytes. They didn’t last long and mostly caught fire after a few minutes BUT they actually had measurable capacitance and did the job after they were initially “formed” with a model train power supply

author: janoc
author_rank: Super Contributor
timestamp: July 15, 2018, 11:53:24 am
content: Our favorite unibrow guy has recently posted a video on Leyden jar capacitors too:

author: Nusa
author_rank: Super Contributor
timestamp: July 15, 2018, 12:31:15 pm
content: Variable air capacitors are tedious to make by hand, but it's not that difficult once you've designed what you want.If I ever did it again, I think I'd set up a CNC program to cut all the rotors, stators and brackets out.