| 摘要 |
1,040,715. Transistor pulse generators. MINE SAFETY APPLIANCES CO. May 31, 1963, No. 21938/63. Heading H3T. [Also in Division G1] A free running transistorized multivibrator circuit 3 which alternately drives transistors 16 and 17 into conduction, supplies current to radiation sources 29, 30 in a density-measuring system (see Division G1). A variable resistor 43 in a divider network including resistors 42, 44 across a battery 13 controls the conduction of a transistor 41 which in turn controls the conduction of transistor 17 and thus the intensity of the source 30. Similarly the intensity of the source 29 is controlled by the transistor 16 whose conductivity is controlled by a transistor 22 having its base connected to the junction of a pair of resistors 23, 24 forming a divider across the battery 13. In the event of any difference in the emergent radiations from the cells 32 and 33 a difference signal is fed from the detector unit 39 to an amplifier 46 whose resultant output is then fed from the detector unit 39 to an amplifier 46 whose resultant output is then fed along line 25 to a circuit consisting of resistors 27, 28 and capacitor 26, to control the conductance of transistor 22 and hence the intensity of the radiation from the source 29 until balance of the beams emerging from the cells 32, 33 is achieved. The difference in intensity of radiation from the sources 29, 30 is measured on a voltmeter 45 whose indication is taken as a measure of the comparative densities of the specimens. |
