Abstract: An S-O-S distress signalling device for flashing a lamp, consisting of a decade binary counter, a signal converter circuit connected to the counter and a timer having its output coupled to the lamp and the input of the counter. The counter and converter circuits provide three charging paths to the timer, so that rapid flashes will be produced to simulate the "S" code and two charging paths to the timer to simulate the "O" code at a slower repetition rate. Between each S-O-S signal, only one charging path is provided, to slow down the timer to define the interval between the coded messages.

Abstract: A watt-hour counter for supplying electrical energy at a remote location from an external power source having a housing with a connection to an external source of electrical power, at least one electrical output mounted externally in the housing and a current measuring means serially connected between the external power source and the electrical output, for producing an output potential proportional to the current at the electrical output. A rechargeable coulometer is coupled to the output of the current measuring means, so that the current sensing means removes a predetermined magnitude of charge from the coulometer proportional to the ampere-seconds used in the external power lines. There is also a charging circuit coupled to the coulometer for charging the coulometer with a predetermined charge, and a switch means serially connected between the external power source and the output, and coupled to the coulometer for interrupting the power to the output in response to a change in potential of the coulometer.