| 摘要 |
<p>959,620. Automatic control of electric current. GENERAL ELECTRIC CO. Ltd. May 3, 1963 [May 11, 1962], No. 18231/62. Heading G3R. In an automatic current control arrangement the output of an oscillator is fed through a frequency-sensitive network and a rectifier to a load and the frequency of the oscillator is varied so as to maintain the load current constant. As shown, the output of a multivibrator 3, comprising transistors 13, 14, is fed via a filter 4 to the input 27 of a power amplifier 5, comprising a driver and phase-splitter transistor 30 and push-pull connected transistors 31. The output of the power amplifier 5 is rectified by a full-wave rectifier 34, smoothed by capacitors 35, 36 and resistors 37-39 and fed to a load across output lines 11, +. The voltage across the resistor 38, representative of the load current, is fed through lines 40, 41 to a control amplifier, comprising transistors 40, 45, the input of which across a resistor 19 varies the bias to the multivibrator so varying the output frequency so as to tend to maintain the load current constant. The voltage across the resistor 39 is applied to an alarm circuit 42. When two similar arrangements are connected in series to a common load the multivibrator centre-frequencies differ to avoid low-frequency beats and the performance of one arrangement is degraded by a shunt resistor.</p> |
