The Wieck Special

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The Wieck Special is the nickname for the test device I am designing. It is an isolated autotransformer which is equipped with current and voltage meters which allow the device under test to be monitored. While the design has changed little from the beginning, it's proposed innards have changed. Originally, this unit was slated to use a gen-u-ine General Radio 10A Variac (the term "variac" has become a generic term nowadays, like "band-aid," but few know that "Variac" was originally a trademark of General Radio Corp.) and a 5A or larger isolation transformer, but I recently acquired a 3A Powerstat variable transformer, and have decided to use that instead since few radios draw more than 3A, and plus, this allows for a smaller (and thus less-expensive) 3A isolation transformer to be used. The current draw meter was originally proposed to be one with a 5A scale (which would've employed a shunt resistor to drop the scale down to 1A for smaller radios), but a more-acceptable 2A meter has been acquired recently.


The projected design of the case!


The proposed schematic!

The Mini-Wieck!

While the full-size Wieck Special is still in planning, I actually have built a smaller-scale version of it. The Mini-Wieck, as I've termed it, uses a small (about 2" in diameter, and quite shallow) Powerstat 10-B 2.25A autotransformer to control voltage output, and a 1 ohm power resistor as a shunt, to allow for a standard AC voltmeter (in most cases, my Simpson 260 set to the 2.5V scale) to act as a current meter. I built this device into the case of an old burnt-out 12V power supply, and it regularly feeds power to my R-390A/URR receiver. Here is a schematic: