ES334527A1 - Electronic device for automatic indication,registration and forecast of local and distant thunderstorms - Google Patents

Abstract

In an apparatus for indicating and recording lightning strikes a rotatably mounted tuned ferrite antenna A detects signals from the strikes in the frequency ranges 0À5-10 Kc/s. and 1-10 Mc/s. and passes them via a selective amplifier V to a rectifier GL. This produces D.C. impulses, each corresponding to a lightning strike. To determine the average intensity of the strikes the impulses are integrated by a first resistor-capacitor circuit RICI, RI1CI1, the average being taken over the period determined by the time constant of the circuit (5-60 mins.). The intensity is indicated by the meter JI in series with resistor R 1 11 across the capacitor C 1 1. To count the lightning strikes, the impulses are used to energize relay Re 1 , whose contacts r 1 change to enable the capacitor C 2 to charge from the battery B. When the relay is released, the contacts change back so that C 2 discharges to the much larger capacitor C 2 1. The voltage across this is measured by meter J 2 in series with resistor R 2 11, to represent the number of strikes. To measure the time for which the strikes occur the output from the rectifier GL is used to trigger a thyristor Th. While this is conducting, a capacitor C 3 is charged from the battery ZI. The charge acquired by C 3 is then determined by the meter J 3 , in series with resistor R 3 11 to indicate the time. The centre of the thunder-storm is located by adjusting the antenna. Instead of using the capacitive circuits referred to above for counting the strikes, the impulses from the rectifier may be supplied to heat a winding (HW) in an insulated enclosure coupled by a mercury filled capillary to a second enclosure maintained at ambient temperature. The movement of the mercury indicates the number of input pulses. Alternatively a stepping motor may be used to count the strikes (Figs. 3 and 4, not shown). The output indicators associated with the system may have special scales so marked and expanded as to warn of the increasing intensity, and thus the nearness, of the lightning strikes. The indicators may co-operate with a barograph to provide marks on the record thereof representing the lightning strikes as they occur.