Abstract: An attenuator, which can readily provide balanced as well as unbalanced attenuation in a plurality of external circuits, includes first and second circuit substrate devices and an actuating device associated with the circuit substrate devices. The first and second circuit substrate devices each provide variable magnitudes of attenuation to respective ones of the external circuits such as, for example, signal transmission lines. The actuating device couples the first in the alternative, and second circuit substrate devices simultaneously or the first and second circuit substrate devices separately to their respective external circuits so as to produce desired magnitudes of balanced or unbalanced attenuation in the external circuits.