This circuit is intriguing…a single transistor power converter that steps up the voltage to any value the load can take. It’s more like a pulsed current source.
Yes and no (your question is invalid/underspecified), with voltage source (constant voltage), current is consequence of device power demand at required voltage. More power required at a given voltage, more current will flow. Less power required, less current will flow, but voltage stays constant. So, ALL voltage regulators are "dropping" current, so your question could be answered by "any voltage regulator, for example LM7805". But if some device requests some power and your regulator's power source can't provide that power, your voltage will drop.
You mean a voltage regulator? That is possible to build but not with this circuit (Joule thief).
The Joule thief charges an inductor in one half of each cycles, and let’s it discharge into the load in the next half. Inductors like to emit a constant current and will kick up the voltage to maintain the current, so it’s more like a current source. Because it drops to 0 quickly before the transistor starts charging it again, it delivers its output as a series of pulses.
So it’s a pulsed current source. The only way to get a constant voltage out of it is to 1) feed the current into a fixed resistance load 2) filter the output via a capacitor.
I thought about how to make a single transistor voltage source but I gave up. Transistors are so cheap there’s not much point. The world has a bizarre preference for voltage sources (maybe due to the fact that early batteries were DC, or maybe it’s just Edison’s ghost). Most real-world loads have useful outputs proportional to current (LEDs, magnetic fields) and the voltage is just a secondary variable.
It might be suitable for miniaturization.