Abstract: A turns-to-arm sensor which uses a piezoelectric crystal to produce a current flow dependent upon the spin rate of a projectile. An output voltage is produced across a diode, from said current, which is proportional to the square root of the voltage at the crystal. The output voltage is approximately equal to the angular velocity of the projectile and is converted to frequency. The frequency determines the rate at which a preset counter operates. At time-out of the counter an arming signal is sent.

Abstract: A photovoltaic power supply and battery charging system comprises a photovoltaic solar energy power supply panel connected through a blocking diode to a secondary storage battery which, in turn, is connected to a suitable load. A temperature sensitive reference voltage is supplied to one input of a voltage comparator, the other input to which is connected to the battery and thereby varies in accordance with the variations of charge on the battery. A short circuit shunt switch is connected directly across the photovoltaic panel; and this shunt switch is opened for varying periods of time by the output of a variable pulse width generator. The pulse width generator, in turn, is connected to and is controlled by the output of the voltage comparator to produce pulses of different widths. The charging current supplied to the battery then occurs in the form of high current pulses of varying widths depending upon the charge state of the battery.