| 摘要 |
980, 200. Electric selective signalling systems. SIEMENS-SCHUCKERTWERKE A. G. April 6, 1962 [April 6, 1961], No.13462/62. Heading G4H. [Also in Division H3] A circuit for producing pulses the frequency of which is related to the value of a current, more particularly for use in an integrating system, comprises a capacitor 1 connected in parallel with the series combination of a first transistor 2 and a resistor 3 and also in parallel with a second transistor 4 and the primary winding 5 of a transformer the secondary of which is connected to the input circuit of the first transistor this electrode also being connected to a Zener diode the circuit being such that the current Je charges the capacitor until the Zener diode becomes conductive and renders the first transistor conducting, the current through this transistor causing the second transistor 4 also to conduct so that the capacitor is rapidly discharged. The circuit shown oscillates at a frequency depending upon the current charging the capacitor producing output pulses which may be applied to a counter to indicate the integral of the input current. |
