SAME POLARITY TRIGGER PULSE FORMING CIRCUIT

PURPOSE: To form a of the trigger pulse same polarity through the input of a step waveform with a single power supply and a simple circuit configuration by forming the circuit with a differentiation circuit and a differential amplifier circuit and outputting a trigger pulse with unified polarity synchronously with a rising and a trailing time of an input signal. CONSTITUTION: An input signal is given to a differentiation circuit 1. Since a diode D1 is reverse-biased for a positive pulse (rising of input signal) in a differentiation waveform outputted from the differentiation circuit 1, no input signal is applied to a transistor(TR) Q1 of a differential amplifier circuit 2, diodes D2 , D3 are conductive and a TRQ2 is conductive. Then an emitter potential of the TRQ2 gets hither and a positive pulse from the diodes D2 , D3 is given to the emitter of the TRQ1 acting as a base ground amplifier and a pulse with the same polarity as the positive pulse is obtained at the collector. When a negative pulse (trailing of input signal) is received, the diode D1 is conductive and the diodes D2 , D3 are cut off and the TRQ1 acts like an emitter amplifier circuit and a pulse whose polarity is inverted from the negative pulse is obtained at the collector of the TRQ1 .