GB889028A - Improvements in and relating to electric pulse forming circuit arrangements - Google Patents

Abstract

889,028. Transistor pulse circuits. CONTRAVES A.G. Feb. 28, 1958 [March 1, 1957], No. 6605/58. Class 40(6). A variable pulse delay circuit comprises an electronic switch which is periodically operable to charge a capacitor, a second switch operable to discharge the capacitor at a rate dependent upon a control voltage applied to the second switch, and a third electronic switch which becomes conductive when the capacitor discharges to the value of a voltage applied to the third switch. Upon the occurrence of an input pulse from a multi-vibrator MV a transistor Tl is momentarily rendered conducting to charge a capacitor C until it reaches the voltage of a battery B2 to which the capacitor is connected by a clamping diode Dl. At the end of the input pulse the capacitor discharges linearly through a transistor T2 arranged as a constant current device, the rate of discharge being dependent upon the current supplied to the emitter through a variable resistor P1. The voltage on the condenser is applied to a transistor T3 where it is compared with the voltage from a potentiometer P2 and, when it falls below the potentiometer voltage the transistor T3 becomes conductive and remains so until the next input pulse is applied to transistor Tl. Pulses are accordingly produced in the collector circuit which are amplified in an output transistor T4, the width of the output pulses being linearly dependent upon the value of the voltage obtained from the potentiometer P2 and also on the setting of P1. A silicon diode D2 increases the apparent resistance of transistor T3 when it is not conducting.