Abstract: The concepts relate to in-line shunting of fuel cells. In one case, a fuel cell stack can include multiple serially arranged cells. The multiple serially arranged cells can be compressed against one another and can be supplied by a fuel supply manifold that is integral and internal to the fuel cell stack. A power source can be electrically coupled with the fuel cell stack at a bus. A controller can be configured to shunt sub-sets of the fuel cell stack while the fuel cell stack continues to supply power to the bus.

Abstract: This invention depicts a novel sine wave ring generator for use with a telephone circuit and an input voltage having a predetermined range, the generator comprising a switching power supply for providing a pre-determined DC output voltage from the input voltage range, an oscillator for providing a pseudo-sine wave output with a predetermined frequency, and an amplifier for amplifying the pseudo-sine wave and for receiving the predetermined DC voltage having a low output impedance thereby maintaining regulation of a circuit output voltage in a predetermined range and supplying a circuit output current.

Abstract: A current regulator for supplying dc power to a telephone line employs a resistor feed circuit in conjunction with a solid state feed circuit. The dc line current flowing through both such elements is monitored by a sensing circuit which drives the solid state element in a manner to maintain a desired magnitude of dc line current. The resistor value may be arbitrarily chosen so that the circuit power is shared in a desired proportion between the resistor and solid state element. When used in a telephone line in series with ac voice signals the regulator employs a capacitator and diode bridge arrangement to reduce the ac impedance thereof, improve longitudinal balance and allow bi-directional current.