I have 14 gauge wire and some 28 gauge wire. Do both lengths of wire have to be insulated? Is it as easy as winding the 14gauge wire top to bottom and then do the 28 gauge wire top to bottom also? I'm guessing this is a step up transformer because the battery is going through the 14 gauge wire and then the lightbulb is hooked to the 28 gauge wire?Does the direction on winding matter at all? Say, CW for the 14g and then CW with the 28 gauge?
ferrite rods are not customarily used for transformers. at RF they are sometimes used as a core for a loop antenna. your application sounds like an ignition coil as you need an interrupter on the DC input (like points on a car ignition). the primary wire (14 gauge) would just be a few turns and not likely to run the full length top to bottom, the secondary (28 gauge) would be a lot of turns like 10 or 20 times as many. direction of winding would not matter in this application as capacitive coupling between the windings should be insignificant. all wire has to be insulated as a shorted turn spoils the transformer effect. wire used for transformers is customarily insulated with lacquer as plastic adds too much bulk to make tight windings. if you already have bare wire, then you made have some success by dipping the wire in lacquer paint first. it sounds like you are duplicating a project you have seen elsewhere. without knowing the source, it is hard for us to guess what the circuit parameters need to be for the transformer. but as i pointed out initially, i am skeptical that you will get this to function in the manner you are expecting. AC power transformers of the kind that use these wire gauges always use a torroidal core ferrite, never a rod. static DC cannot be transformed at all.
