Abstract: Unique fired clay pillows are described which are useful for a variety of purposes. They have particular utility in structural applications when they are first rendered impervious, mixed with a hardenable binder, and then cast into a mold or form of desired size and configuration where the binder is hardened, thereby producing a consolidated pillow structure having a high degree of void space. The consolidated pillow structure is fire-resistant, weather-resistant, rot-proof, and exhibits good sound absorption and thermal insulation properties.

Abstract: A simplified voltage regulating circuit is provided for controlling the operation of a d-c to d-c converter oscillator as is commonly used in an electronic flash. The voltage regulating circuit controls the operation of the d-c to d-c converter so that the output voltage from the oscillator is maintained within a prescribed range. The voltage regulating control circuitry includes an ordinary transistor controlled by way of an output voltage sensing zener diode which operates to turn on the transistor and thereby terminate operation of the oscillator when the output voltage therefrom reaches its maximum value within the prescribed range. A capacitor is also charged by way of the transistor when it turns on and the residual charge of the capacitor thereafter operates regardless of the non-conductive state thereafter assumed by the zener diode and transistor to maintain the oscillator off until the output voltage from the oscillator decays to its minimum value within the prescribed range.

Abstract: A quench strobe is provided with a resistor for effecting the quenching thereof at a predetermined rate which controls the amount of exposure influencing artificial illumination emitted subsequent to the quench trigger signal so that such exposure influencing artificial illumination closely correlates to the amount of exposure influencing illumination normally expected subsequent to the command signal to close the camera shutter blade elements and automatically anticipated by the camera exposure control system.

Abstract: A transponder transmitter for transmitting over power lines includes a rectifier circuit that rectifies the power at power line frequency to provide a unipolar potential having ripple at twice the power line frequency. A circuit receives a drive signal from a modulator for interrupting the unipolar potential at a rate corresponding to the carrier frequency of the modulating signal. Circuitry, including a triac couples the interrupted unipolar potential to the power lines.