| 摘要 |
<p>1339908 Transistor amplifying circuits PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd 22 Dec 1970 [25 Dec 1969] 60825/70 Heading H3T [Also in Division G3] A current i 0 , Fig. 1, of small value is derived from the collector of a transistor T 1 , the base of which is biased from the voltage drop across a rectifying junction, i.e. diode D 1 , comprising a transistor with base and collector strapped, through which a control current i 1 is passed from a current source S 1 . The emitter is biased from the voltage drop across a resistor R through which a cutrent i 2 is passed from a current source S 2 . The arrangement may be rendered insensitive to temperature changes by using as resistor R a temperature sensitive device, or by making the current source S 1 or S 2 temperature sensitive. In a biasing arrangement for a differential amplifier comprising cascaded emitterfollowers T 6 , T 7 and T 11 , T 10 , Fig. 2, driving transistors T 8 , T 9 respectively which have as collector loads the transistors T 13 , T 12 respectively, the transistors T 6 -T 11 are biased from auxiliary transistors T 1 -T 5 . The bases of the transistors T 1 -T 5 are coupled together and biased from the voltage drop across diode D 1 which is fed from a current source comprising resistor R 8 . The emitters of transistors T 1 -T 5 are biased from a chain of resistors R 1 -R 3 fed from a current source S 2 . The current source S 2 comprises a transistor T 14 , from the emitter of which the control current is obtained; its base is fed from a differential amplifier V, one input of which is fed from a potentiometer chain comprising diode D 2 and resistors R 6 , R 7 . The other input of the differential amplifier V is coupled to the collector circuit of transistor T 14 via feedback transistor T 15 and resistors R 5 , R 7 . In another application, the input of amplifier A, Fig. 3, is biased from the collector of transistor T 1 , the emitter of which is biased from the voltage drop in resistor R. The bases of transistor T 1 and output transistor T 2 are coupled to the output of amplifier A.</p> |
