| 摘要 |
The circuit of the present invention discloses a relaxation oscillator comprising a programmable unijunction transistor which is so controlled that the output frequency may be smoothly shifted between two limits. A first transistor circuit and associated resistors control the charge and discharge rate of a capacitor which is coupled to the anode, or trigger point, of the programmable unijunction transistor. The charge and discharge time of the said capacitor controls, in part, the output frequency. A second transistor circuit and associated resistor control the charge and discharge rate of a second capacitor coupled to the gate of the programmable unijunction transistor. The instantaneous magnitude of the potential of the gate of the programmable unijunction transistor is controlled by said second capacitor; and the magnitude of the voltage at the gate determines the magnitude of the voltage required at the trigger point to render the programmable unijunction transistor conducting.
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