Abstract: A supplemental power source connectable to a standard railroad track switch power source. A pair of electrical connectors (A) form a supplemental power source circuit input. Another pair of electrical connectors (B) form a supplemental power source output and are configured for connection to a standard railroad track switch. An electrical conductor connects a first one of the supplemental power source output connectors (B) to a first one of the supplemental power source input connectors (A). A diode is connected between a second one of the supplemental power source input connectors (A) and a second one of the supplemental power source output connectors (B). The diode is connected to prevent current flow to the standard railroad track switch power source. An ultracapacitor is electrically connected between the electrical conductor and the second one of the supplemental power source output connectors (B).

Abstract: A telephone apparatus powered directly from the telephone lines without external power includes a current converter in which current from a telephone line is limited by a transistor, current-sense resistor, and optical coupler acting together as a constant current device. This limited current is then converted from direct current (d.c.) to alternating current (a.c.) at the primary of a current transformer by power switching transistors driven by a flip-flop which is in turn driven by a free-running constant frequency oscillator. The alternations are symmetrical and their period or timing controlled so the current transformer does not saturate, thus maintaining maximum efficiency of conversion. The transformer outputs, after being rectified and filtered, are isolated from the primary, and provide d.c. current to maintian the charge on a battery across one output and to power telephone circuitry within a telephone device connected to the d.c. outputs.