Abstract: An apparatus for extracorporeal lung assist including a pump device having a flexible blood reservoir housed in a rigid housing, which pump device is able to expand and contract the blood reservoir by pumping liquid into and from the housing, thereby repeating cycles of blood feed and blood take-off, a blood take-off circuit connected to the in-flow side of a membrane artificial lung and in which the pump device is disposed, a blood feed circuit connected to the out-flow side of the membrane artificial lung, the two circuits forming an extracorporeal circulation circuit, a liquid circulation circuit connected to the housing of the pump device and having a flexible liquid reservoir disposed therein with a head provided relative to the pump device, and sensors for detecting the expansion and contraction of the liquid reservoirs, whereby blood in-flow and out-flow paths are controlled so that when the blood reservoir is contracted, blood is drawn into the blood reservoir under subpressure in the housing, whereas

Abstract: A series connection of a pair of dividing capacitors and a series connection of a PNP transistor and an NPN transistor are connected in parallel with a direct current voltage source, a primary winding of a saturable transformer is coupled between the junctions of the respective series connections, the saturable transformer comprising a pair of feedback windings coupled to the primary winding, the pair of feedback windings are connected between the base and emitter electrodes of the respective corresponding transistors through the respective base resistors, the emitter electrodes of the respective transistors being connected to the direct current voltage source sides, a series connection of two capacitors is connected between the junctions of the respective feedback windings and base resistors, and the junction of the two capacitors is connected to the junction of the series connection of the dividing capacitors.