| 摘要 |
1,061,610. Rectifying. STANDARD TELEPHONES & CABLES Ltd. Oct. 15, 1965, No. 43818/65. Heading H2F. [Also in Division H3] A single-phase half-wave rectifier circuit for supplying intermittent current to a load such as a vibrator comprises a semi-conductor controlled rectifier CRI and a control circuit for controlling the phase angle of firing, the control circuit comprising a trigger section and a pulse shaping section which supplies square pulses to the rectifier, the trigger section consisting of two sub circuits, selectable by a switch SWI, which allow the control to be either manual or automatically dependent on the load. With 4-pole 2-way switch in the position shown (automatic control) input at AB from a transducer which senses the load controls a transistor VTI which forms one arm of a bridge R4, R6, VTI+R7, RV2. The diagonal of the bridge is formed by the emitter-base path of a transistor VT2 so that the degree of unbalance is manifested as the current charging a capacitor C2. At a predetermined level of charge the transistor pair VT3, VT4 is triggered providing a signal to the bi-stable pulse forming circuit VT5, VT6 and thence to the rectifier CR1. A Zener diode shunts the pulse-forming network. With the switch SW1 in the other position (contacts 2, 5, 8, 11), the rate of charging of a capacitor C1 is dependent on a manually controlled resistor RV1, the charge on this capacitor triggering the circuit VT3, VT4 as previously described. |
