A very bare bones Hoffman Apparatus I built in high school with the intention to split water into Hydrogen and Oxygen gas. This consisted of two electrodes of steel each with over 500 square inches of surface area. The power source was a full bridge rectifier I had built that I plugged into the AC mains of my home. The 120 RMS voltage was turned into 170 volts DC. At its max power output I was able to draw 9 Amps of current before I had to be concerned with the wiring starting to melt. As you can see from the video there was definitely a lot of gas being liberated, but I was not able to collect it, and I probably should have spent more time designing and investing in a tank and collector system.

A Tesla Coil I made for my senior project in high school. A 12 kV transformer was connected to the AC mains of my house and powered the primary circuit consisting of a parallel plate capacitor, and primary coil of about 10 turns along with two steel bolts forming a spark gap. The secondary circuit had a secondary coil of about 1000 turns of fine gauge copper wire with one end of the inductor grounded with a grounding rod to Earth and the other end attached to an aluminum torus. If all the tuning had been done correctly, this should have reached approximately 1,000,000 volts at the secondary circuit, but I had problems with overcoupling causing the voltages between individual turns of wire on the secondary inductor to be so high that the wires starting melting.

Here is a video of me and my friend Doug testing a 12,000 volt transformer we bought off eBay. One terminal is +6 kV relative to ground and the other terminal is -6 kV relative to ground. You'll notice that even though we are holding the ground wire of the transformer and bringing it up to one of the terminals without any PPE, we did not get electrocuted. This is because the resistance through the ground wire is a lot less than the resitance through ground if the current were to pass through our bodies, and therefore, essentially all the current flows through the ground wire and none through us. However, if you were to touch one of the terminals without holding the ground wire, you would get "bit" and suffer a severe shock and burn. If you were to touch both terminals at once, the full 12 kV would flow through your heart and you would die.