| 摘要 |
PURPOSE: An oscillation prevention apparatus is provided to prevent oscillation in case of current feedback by adding a narrow band transistor to the start-up circuit and lowering gain of the circuit. CONSTITUTION: An oscillation prevention apparatus comprises a resistor(R18) and a transistor(Q24) connected in serial between a power and an earth; a transistor(Q23) having a base connected to the base of the transistor(Q24); transistors(Q20-1,Q20-2,Q21) connected in parallel to the collector of the transistor(Q23); resistors(R39,R40) connected to emitters of the transistors(Q20-2,Q21); a transistor(Q21-1) having a base connected to the collector of the transistor(Q21) and a collector connected to the collector of the transistor(Q23); a resistor(R20) connected in common between the earth and emitter connecting terminals of the transistors(Q23,Q21-1); and a narrow band transistor having a base connected to the base of the transistor(Q21-1) and a collector connected to the collector connecting terminals of the transistors(Q23,Q21-1).
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