| 摘要 |
1,254,296. Transistor sawtooth generators. HONEY WELL Inc. 29 Nov., 1968 [10 Jan., 1968], No. 56855/68. Heading H3T. A sawtooth generator has a capacitor 20 charged from a constant current source 54, and a voltage sensitive switch comprising, for example, a Zener diode 82 and an S.C.R. 84, which produces a pulse when the sawtooth reaches a predetermined level, to operate a monostable 98, 108 which shorts out the capacitor 20 for a given time, such as by turning on a transistor 22. The constant current is adjustable by a switch 58, and the negative reference level of the sawtooth is adjusted by a potentiometer 42. The voltage on the capacitor 20 is transmitted by a Darlington pair 62, 64 to the Zener diode 82. When the S.C.R. conducts, upon the capacitor reaching the predetermined voltage, its cathode positive-going voltage is differentiated at 94 and triggers the monostable 98, 108 into its unstable state. The duration of this is adjustable at 122. During the unstable period transistor 22 conducts to discharge capacitor 20. It is said that valves and switches may be used instead of transistors. |
