Abstract: A surface acoustic wave variable time delay includes a surface acoustic wave device (10) which is secured within a housing (30). The device (10) is provided with an input transducer (12) and an output transducer (16) which are respectfully connected to input lines (14) and output lines (18). An electrostrictive element (20) is secured within housing (30) between an end of device (10) and an interior wall (34) of housing (30). A control signal is applied to electrodes (22, 24) connected to element (20) to vary the size thereof. Element (20) applies a mechanical force to the surface acoustic wave device (10) to alter the distance between the input transducer (12) and output transducer (16) to thereby control the delay time between the signal supplied to the input lines (14) and the output signal at the output lines (18).

Abstract: A solid state digital running time indicator is energized from the same power source supplying energy to a monitored event. A device for detecting when the power is on initiates a signal to timing circuitry for generating clock pulse signals and control timing signals. In response to an initial timing signal, a memory element reads the information from memory into a counter chain. The clock pulse signals are applied to the counter chain for counting up in predetermined increments of time from the number that is initially loaded into the counter chain from the memory element. Control circuitry writes the contents of the counter chain into the memory element after each predetermined increment of time. The total accumulated running time present in the counter chain is applied to drive and display circuitry for providing a visual indication of the running time of the event being monitored.