This circuit is a basic theremin with only a pitch control. It uses the `heterodyne` technique, as did Theremin`s original instrument. Heterodyning is advantageous in its simplicity, and is made further attractive in this design by eliminating the coils that are usually hard to find. Although this is a simple theremin without optimized sensitivity and noise characteristics, it is a viable performance instrument.
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This project is intended for those with medium to high-level skills in electronics assembly and troubleshooting. An oscilloscope and frequency counter are recommended in the event measurements are required. If you aren`t inclined to deal with these issues, commercial theremin kits such as the Minimum Theremin Kit from Harrison Instruments may be a better choice. When deciding between a "do-it-yourself" or kit-built theremin, be aware that electronic materials can be expensive. Some items can only be purchased in bulk quantities, and many distributors impose "minimum order" requirements. Since it ’s unlikely you will find all the parts in one place, also consider the effort required to make many phone calls and write several orders. Of course, if you are equipped with a well-furnished electronics lab, then you may save considerably by building the Wien-Bridge Theremin, using parts you have on-hand. Max Wien was born December 25, 1866 in KG¶nigsberg (presently Kaliningrad, Russia). While at the Institute of Physics at the University of Berlin, he developed the two-resistor, two-capacitor frequency-determining network that is used in this theremin`s oscillators. Wien published his work in Annalen Der Physik und Chemie in 1891 in the treatise, Messung der Inductionsconstanten mit dem "optischen Telephon" (Measurement of Inductive Constants with the "Optical Telephone"), in which he describes the use of bridge circuits for the...
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This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
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