Above: A modern theremin, the Moog Etherwave Standard theremin is smaller than the RCA theremins, and has but one small circuit bard inside. At each end of this board is a set of tiny coils which produce the radio magnetic feild which surrounds the two antennae. Like the classic theremins, modern theremins function in much the same way. The oscilators in modern theremins aer in the form of transistors. You can evin find integrated circuit chips on these boards. Mouse over the image of the Etherwave Standard to see what's inside, and click to see a large image of the unbuilt kit version, which is still produced today!

Left: An antique RCA theremin built around 1928 to 1929. Fewer than five hundred were produced, and only between one, and two hundred are known to exist, with half of those being functional. Mouse over the image of the RCA, and click to see what's inside.