| 摘要 |
1,196,186. Transistor reference voltage switching circuits. LITTON INDUSTRIES Inc. 23 Feb., 1968 [6 March, 1967], No. 29598/69. Divided out of 1,196,185. Heading H3T. A circuit for switching a reference D.C. or A.C. voltage to a load comprises a first switch 50 connecting the reference voltage source 54 and a second switch 52 connecting a further source 56 through a resistor 58 to the load, to supply most of the load current, a further switch being connected across the load. The switches shown are field effect transistors and as most of the load current is supplied from the second voltage source, the current from the reference source is small and the voltage drop across switch 50 is also small. Switch 62 short circuits the load when the other switches are off and a further switch (64, Fig. 4, not shown) may become conductive when 52 is off to prevent the full voltage of source 56 being applied to 52. The circuit is described as applied to the digital to analogue conversion circuit of the parent Specification. |
