I took apart a wall transformer before and soldered a single AA battery to the outputs and touched the what was before inputs and it gave me a shock. This is because it stepped up the power to something like 113v. Could I instead of a AA battery use 110 from the wall. Would it do the same thing. Or would it just overheat the transformer. And what would the amps be. I’m trying to make like a 20amp welder for just screwing around with.
A standard transformer can step up the volts, sure. It's the basic isea behind things like a Tesla coil. It can also kill you. It's the volts that jolts, but its the mills (milli amps) that kills. A battery can't provide enough oomph to kill you. A 110v wall connection will do it without breaking a sweat. The small transformer might fizzle, buit that will be small comfort to those who find your corpse.
Another reason not to put transformers backwards is that the insulation on the coils will very probably not take the voltage. Say you get 2400V out of a transformer - the 2400V will be on coils insulated for 120V, and the coils on which you put 120V were insulated for 6V. So the insulation will likely fail. Short circuit. Electrical fire. Toxic smoke, house burnt down. Grounded until 65.
A battery will not work with a transformer. Transformers rely on alternating current (AC), whereas a battery provides only direct current (DC). The voltage at the output terminals will be zero, except for the instant at which you connect/disconnect the battery. Be very careful working with transformers, as they can create deadly voltages. Also, connecting/disconnecting an inductor can create enormous transient voltages across the terminals (especially if a DC current was applied), causing a spark. The step-up equation for a transformer is V1/V2 N1/N2 For example, if you connect the 110VAC wall outlet to a 10,000-turn solenoid, and the output terminals are connected to a 200,000-turn solenoid, the output terminals will be 2200VAC. Alternatively, due to conservation of energy, the current will be inversely proportional to the winding ratio.
To answer your basic question I’m trying to make like a 20amp welder for just screwing around with. Look at the rating on the transformer, most wall transformers will tell you what wattage and voltage the transformer is rated. If it says 9 watts at 1.5 volts that is all it will do no matter what you do. You can put a chopped DC on the 1.5 volt secondary and get 115 volts on the primary but at a greatly reduced current (about .075 amps max). That is the best that transformer will do but because you are using a square wave you will be a less than an optimum power transfer. If you want 20 amps at 110 volts that is some substantial power and dangerous. D.bumstead
You will blow fuses DO NOT TAMPER WITH THINGS YOU DON'T UNDERSTAND a primary winding has enough turns to reduce magnetizing current to a few mA you put lots of volts on a few turns (secondary) and the core will overheat, that's if the primary does flash over (a battery momentarily connected will cause a corresponding stepped up voltage pulse on the primary) A permanent connection will flatten the battery (almost a dead short)
