wattmeter - measuring electric power the electronic way!

wattmeter elektor may 1983 How much current is drawn by a dimmed light-bulb? Does the extractor fan actually "consume" the rated power specified by the manufacturer? What output power can I expect from my home-made windpowered generator? Or even: What is the power consumption of my super hi-fi FET power output stage? All these questions, and more, can be answered simply, using an electronic wattmeter. watt-meter If the wattmeter is expanded to a kilowatt- hour meter by adding a suitable extension electric power circuit (this will probably appear in the measuring the electronic way! June issue), the user will also be able to answer the following questions: How much can I save by placing the refriger- ator in a cool room and what is its average consumption per week? What contribution to energy saving is made by insulating the electric boiler? What is the cost of a "machine wash" at 90°, compared with one at 60°? The wattmeter can be used simply and safely as an intermediate socket...