The Less-Than-Ideal Transformer

article by Ben Lincoln

The Less-Than-Ideal Transformer is a component that I built myself (rather than buy) for the RF Signal Degrader. It was an attempt to create the worst isolation transformer of all time. In this respect, it almost certainly failed, because despite my best efforts it actually works reasonably well.

It uses a toroid (or "toroidoid", if you will) design. In a traditional transformer, the core is made of iron or another material of high "magnetic permeability" (also known as "magnetic coercivity", or having the property of being "magnetically soft"). In a deliberate attempt to sabotage the end product at this basic level, I constructed the core from three magnets salvaged from old hard drives, held together via nuts and bolts passed through their original mounting holes.

An isolation transformer is supposed to have an equal number of turns for both the primary and secondary windings. I didn't want to significantly alter the voltage, but I also felt that some change was necessary in order to break this design rule as well. Therefore I used a fairly high number of turns, with the primary having about 47 and the secondary having either 46 or 48. I deliberately performed inconsistent work on the windings, with them being spaced unevenly around the core.

Construction of The Less-Than-Ideal Transformer

Back of the Toroid

Front of the Toroid

Primary Winding

Secondary Winding

Date Shot: 2009-03-04
Camera Body: HTC Dream / T-Mobile G1
Lens: Unknown
Filters: None
Date Processed: 2009-03-04
Version: 1.0

I didn't have time to perform measurements on the transformer before using it in the RF Signal Degrader, but it actually ended up serving the opposite purpose for which I'd originally intended it: without the transformer inline, the RF signal was more noisy than with it. I suppose this can serve as a lesson for those who like to improvise things in the style of MacGyver - it's possible to put together a reasonably-effective transformer from junk parts even with no prior experience.