Fools as i carry with me all of human knowledge, right here in this fragile tiny black slab. I can tell you all once you tell me what your wifi password is.
This book
Tells you how to handle this, along with everything else you need to know to rebuild all systems in society from scratch should there be some sort of time machine based accident. It’s a good read!
There was a short story I read ages ago in some collection somewhere I've been dying to find. I think it was from the 60s or 70s, but a scientist brings a man from the future and the man is just a normal guy, so he can't explain anything to the scientist's satisfaction and the scientist gets more and more exasperated.
The dialogue was like:
"What is the dominant mode of transport in the future?"
"Oh, we fleem."
"Fleem? What's fleem?"
"It's a kind of garbol but with more slimp."
"Okay, never mind. How do you do it?"
"Oh, that's easy, you simply merfingle the blem and you're fleeming away!"
Let's see... electricity in a preindustrial environment. You'll get into Factorio levels of invent a tool to make a tool to make a tool...
Copper wire existed at the time, (depending on the time period) but drawing it involved a person on a swing pulling it through a hole in a metal plate. So we need a metal plate. Surely there is a town blacksmith? We will need a few plates with gradually decreasing hole diameter. Enough wire for a demonstration would be difficult and expensive, but not impossible. Could also use copper busbars instead of wire.
Now that we have conductors, we have to figure out what method of generation we want. Rather than trying to make bearings, balanced shafts, and stacks of thin metal plates all identical and radially symmetrical so we can make a generator, we should first attempt a battery. For this we can get away with stacks of two dissimilar metals in a glass or ceramic jar, bathed in some sulfuric acid. Aqua Regia was a mixture of nitric acid and sulfuric acid, but it might dissolve copper and zinc plates. Could also use lead plates, those are easier to hammer out flat. With this we could get an output around 2v per cell, put a half dozen of them together in series and one could build a simple arc lamp.
After the proof of concept demonstration, hopefully you'd interest more smiths in the project, increasing your talent pool. With some mercury and wire you could build a version of Faraday's homopolar motor.
It isn't so hard really, to make electricity even in the olden days.
A dynamo is just a copper wire with a magnet spinning inside.
Making a copper wire you can accomplish by having a hole at the bottom of a kiln that drops directly into a big vat of water. Or even just drawing a line in the sand and pouring it in there.
Getting your hands on a natural magnet might pose more problems, but ultimately those are found in nature. So they should have already been dug up by someone.
Using the electricity usefully is harder. Since creating a light bulb needs access to gasses. What could we even use the electricity for?
For anyone interested a simple way is to wrap copper wire around a magnet. Static electricity was also one of the first ways people started noticing electricity.
Parlor tricks might be able to get you far when you time travel to the ancient past.
First of all, no one would understand you, but how someone already pointed out, make a spool with copper and spin it. For bonus points, put a iron slab inside the spool
Edit: as someone pointed out you kinda need a magnet
If you could find a jeweller and had an understanding of basic electrical systems, you could probably get a rudimentary capacitor and engine going. From there, who knows what you could do. Maybe even lightbulbs.