2025 Component Abuse Challenge: Boosting Voltage With Just a Wire
Switching power supplies are familiar to Hackaday readers, whether they have a fairly conventional transformer, are a buck, a boost, or a flyback design. There’s nearly always an inductor involved, whose rapid change in magnetic flux is harnessed to do voltage magic. [Craig D] has made a switching voltage booster that doesn’t use an inductor, instead it’s using a length of conductor, and no, it’s not using the inductance of that conductor as a store of magnetic flux.
Instead it’s making clever use of reflected short pulses in a transmission line for its operation. Electronics students learn all about this in an experiment in which they fire pulses down a length of coax cable and observe their reflections on an oscilloscope, and his circuit is very similar but with careful selection of pulse timing. The idea is that instead of reflected pulses canceling out, they arrive back at the start of the conductor just in time to meet a pulse transition. This causes them to add rather than subtract, and the resulting higher voltage pulse sets off down the conductor again to repeat the process. We can understand the description, but this is evidently one to sit down at the bench and experiment with to fully get to grips with.
[Craig]’s conductor is an alternative to a long coil of coax, a home made delay line of the type once found in the luminance circuit of some color TVs. It’s a coaxial cable in which the outer is formed of a tightly wound coil rather than a solid tube. With it and a high-speed gate driver he can light a couple of neon bulbs, a significant step-up, we think. We’re trying to work out which component is being abused here (other than the gate driver chip he blows) as the conductor is simply performing its natural function. Either way it’s a clever and unexpected circuit, and if it works, we like it.
This project is part of the Hackaday Component Abuse Challenge, in which competitors take humble parts and push them into applications they were never intended for. You still have time to submit your own work, so give it a go!
