Abstract: A cylinder apparatus includes a cylinder having a hydraulic fluid sealed therein. A piston rod is connected at one end thereof to a piston slidably fitted in the cylinder. The other end of the piston rod extends to the outside of the cylinder through a seal device provided at the opening end of the cylinder. The seal device has a rod seal and a backup mechanism that presses the rod seal against the piston rod. The backup mechanism has a ring-shaped resilient member provided on the upper surface of a ring-shaped support plate clamped between a rod guide and a seal cap. The ring-shaped resilient member is elastically deformed by an annular tapered wall formed on the seal cap, thereby applying a backup force to the rod seal. Thus, the force with which the rod seal is pressed against the piston rod is kept substantially constant.

Abstract: This electric power supply system includes an air conditioner serving as load, a solar photovoltaic cell for supplying power to the air conditioner, and a system power control circuit and further including a commercial power source for use in combination with the solar photovoltaic cell for supplying additional power when insufficient, power is supplied from the solar photovoltaic cell to the air conditioner. In an operation state of the air conditioner, the system power control circuit operates to regulate an operating point of the solar photovoltaic cell and variably regulate the supplied power from the solar photovoltaic cell while comparing required power of the air conditioner with the supplied power from the solar photovoltaic cell.

Abstract: A driving circuit for an inverter microwave oven which includes a push-pull voltage type inverter circuit having two sets of switching element groups each provided with more than two switching elements connected in parallel to each other for switching the D.C. current supplied from a D.C. power source, a control device arranged to set a period for simultaneously turning OFF the two sets of switching element groups and to alternately turn ON the switching element groups by the same duty cycle, a step up transformer supplied, at its primary winding having a center tap, with A.C. current from the inverter circuit, and a voltage doubler rectifier circuit connected to a secondary winding of the step-up transformer for supplying electric power to a magnetron through a capacitor.