This report is devoted for the most part to a des¬cription of a basic trigger circuit element containing two similar (i.e. n-p-n or p-n-p) transistors. The circuit employs coupling between emitters and from one collector to the other base with clamping diodes serving the dual function of stabiliz¬ing operating conditions and preventing collector saturation in both transistors. Suitable choice of component values and volt¬age supplies yields circuits capable of astable, mono-stable or bistable operation. The virtues claimed for the circuit in¬clude a high impedance sensitive input;a low impedance output point and also an output point which is external to the feed¬back loop and which can therefore be loaded in any reasonable way without affecting circuit operation. Variants of the basic circuit which provide a fast recovery, accurate trigger thres-hold and a variety of other features are described.
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