Abstract: A matching circuit is connected between a source circuit and a load circuit. The matching circuit is made up of an impedance transforming circuit and a balance-to-unbalance signal-transforming circuit. If necessary, means for blocking the DC components intervene between those transforming circuits. The impedance transforming circuit is made up of inductive and capacitive elements. The matching circuit is reversible.

Abstract: A pneumatically operated nailing machine for driving nails by a main piston operated by compressed air. A nail feeding piston is actuated by compressed air, synchronous with the movement of the main piston. To make the feeding of nails smooth, a device to accelerate evacuation of compressed air from the nail feeding piston is attached and the nail feeding piston is resiliently engaged with a nail feeding pawl. The front end of the nail feeding pawl is provided with a cutting edge for cutting a steel wire connecting the nails. A nail magazine is provided with a flat nail placing plate so that the nails are always fed to a fixed position, and against which each of the contained nails is resiliently pressed. The fitting position of the nail placing plate is changeable to permit the use of nails of different lengths.