Abstract: A portable, battery-powered high capacity dc-dc voltage converter suitable for charging capacitor-based devices such as electronic camera flash lamps is disclosed. The voltage converter utilizes two high frequency metal oxide semiconductor field effect power transistors which are driven in a push-pull arrangement by an emitter-follower full wave bridge circuit. The transistors drive a low leakage inductance toroidal ferrite-core power transformer at a frequency which is sufficiently high to avoid saturation of the transformer, resulting in high efficiency and low power consumption. The output of the transformer is rectified to produce a high capacity dc charging signal on the order of 300 volts with a maximum current of 28 amps. The voltage converter is capable of recharging commercially available inexpensive electronic 100-watt flash lamps at a rate of once every 1.8 seconds, compared with a rate of 15 seconds for comparable prior art self-contained charging units.

Abstract: A mounting fixture for supporting up to two electronic flash lamps and a reflective light umbrella on a photographic light stand is disclosed. The fixture includes two orthogonal flash lamp shoe brackets and an integral deflectable locking arm for securing the fixture body to a vertical post of a light stand. A locking bolt passes through coaxial bores in the arm and the fixture body. The locking bolt includes a cylindrical head having a transverse bore for receiving a shaft of a reflective umbrella. A tubular locking collar is interposed on the shaft of the bolt between the fixture body and the head of the locking bolt. The locking collar includes a pair of diametrically opposed semicircular recess cut into its tubular end edge which are alignable with the openings of the bore in the head of the bolt. The locking collar, together with the bolt head, operates to secure an umbrella shaft in place when the bolt is tightened to secure the mounting fixture on a light stand.