| 摘要 |
PURPOSE: To vary a high level output voltage Voh depending on a load circuit by dividing a power supply voltage in series with a 1st resistor by a resistor connected between a base of a 1st transistor(TR) and ground and changing the voltage division ratio. CONSTITUTION: A resistor (R6 ) 30 is connected between a base of a TR (T1 ) 3 and ground. At application of a voltage Vi1 to an input terminal (Vi) 12, a TR (T3 ) 6 is nonconductive and the TR (T1 ) 3 and a TR (T2 ) 4 are conductive and an H level voltage Voh is outputted to a TTL output terminal (Vo) 13 and assuming that a base current of the TR (T1 ) 3 is small, the voltage Voh is expressed as Voh=Vr-VBE1 -VBE2 , where Vr=Vcc×R6 /(R1 +R6 )}, and VBE1 , VBE2 are base-emitter forward voltages of the TRs (T1 , T2 ). Thus, the Voh depends on the voltage division ratio of the Vcc by the resistors (R1 )1, (R6 ) 30 and the Voh varied by changing the resistance of the (R6 ) 30.
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