Anyone who has ever wound a toroidal coil by hand can tell you that it’s not exactly a fun job. Even with the kinds of coils used in chokes and transformers for ham radio, which generally have ...

Sometimes, you find yourself in need of a coil. You could sit around winding thousands of turns of copper wire yourself, but that would be remarkably tedious. Thus, instead, you might follow the ...

Equipment: A flashlight connected in series with a wire coil, a small (~2L) dewar of liquid nitrogen, safety goggles and safety gloves. What it does: When the coil is at room temperature, the ...