Abstract: A bipolar transistor comprising a first layer of a first semiconductor material having a first conductivity type, a second layer on the first layer, the second layer being of a second semiconductor material having a second conductivity type, the second semiconductor material having a bandgap less than that of the first semiconductor material, a third layer on the second layer, the third layer being of the second semiconductor material and having the first conductivity type, a first doped region in the first layer, the first doped region being of the first semiconductor material and being doped to be semi-insulating regions, and a second doped region in the third layer, the second doped region being of the second semiconductor material and being doped to the second conductivity type. The second layer has a portion forming an active base region and the third layer has a portion forming a collector region in contact with the active base region.

Abstract: A battery rapid charging circuit is disclosed which includes a DC power source supplying a DC voltage across first and second terminals between which a battery to be charged is connected, a circuit element for short-circuiting the first and second terminals in a short period of time during a charging period of the battery, a comparator for comparing a terminal voltage of the battery upon the above short-circuiting period with a reference voltage, and a circuit element for stopping the supply of the DC voltage across the first and second terminals in response to the output of the comparator.

Abstract: In a gas-filled space, a pulsed electron beam device comprises a cathode provided with through holes, a filament on one side of the cathode, and an anode on the other side with a sample to be processed held thereon. Electrons emitted by the filament are momentarily directed to the cathode so that a portion thereof may trigger a discharge in a space between the anode and cathode. The discharge ceases in a moment, meanwhile providing electron beams to uniformly process the sample. The cathode may comprise either a single plate of graphite or a combination of a graphite plate and an aluminum plate. Preferably, a net electrode is placed between the cathode and the anode and electrically connected to the anode.