Joule Thief efficiency test 2

Here's my results of testing gadgetmalls circuit, or at least the closest I can presently get to it. I don't have his toroid, but I'm using a good toroid with high permeability & similar size that he describes.

This method consist of using a resistor for the load, and measuring the resistors temperature, which we'll call Tr. Then doing the control experiment, which consists of connecting the resistor directly to a power supply, and then increasing the current until the resistor temperature stabilizes at Tr.

An elaborate setup would use a closed system that maintains a fixed temperature. I did not go that far. Also I did not dig out the ridiculously sensitive temperature equipment.

A 100 ohm carbon resistor was used as the load. The voltage across the JT was 1.559 volts DC, and the current was 74.3mA DC, for a total of 116mW. The control experiment showed that it took only 93.3mW to bring the resistor to the same temperature.

This comes to 80.4% efficient.

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