| 摘要 |
<p>PURPOSE:To prevent noise induction generated due to any cause and to exclded minute fluctuation of an oscillated frequency by adding simply one resistor to a current mirror circuit used as a load of a differential amplifier being a major component. CONSTITUTION:A potential at a point X, VX when transistors (TR) 1, 9, 10 and 11 are cut off is expressed as VX=(R18/R18+RX)VCC, where RX is an impedance viewed from the point X and R18 is a resistance of a resistor 18. Denoting the RX as 250kOMEGA, R18 as 5kOMEGA and VCC as 12V, then the VX is nearly 11.8V. Thus, only a voltage difference of 0.2V is given between the emitter and base of the TRs when the TRs 1, 9, 10 and 11 are cut off. Further, since the impedance at the point X depends nearly on the resistor 18, the resistor 18 is selected and the quantity of change in the oscillation frequency against power supply VCC is reduced.</p> |
