| 摘要 |
PURPOSE:To obtain a bias circuit having excellent compensation function against power voltage fluctuation and temperature change and hardly oscillated by adding an oscillation preventing capacitor only between the base of the 2nd transistor (TR) and the base of the 1st TR. CONSTITUTION:A capacitor for preventing oscillation is inserted between the bases of the TRs Q2 and Q1, or between the collector and base of the TR Q1, or between nodes 1 and 2. The potential fluctuation generated by the node 1 id delivered through the positive feedback loop. Since the capacitor C is inserted between the nodes 1 and 2, since the phase is advanced further in the path from the node 2 to the node 1 in the potential fluctuation delivered along the positive feedback loop, the potential gain is decreased and the bias circuit is hardly oscillated. Since the oscillation is not causes as the phase lead is large in the path from the node 2 to the node 1, the capacitance between the nodes 1 and 2 is to be inserted effectively.
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