by the use of differential amplifiers or comparators, with internal or external positive feedback

Circuits for generating electric pulses; Monostable, bistable or multistable circuits > Generators characterised by the type of circuit or by the means used for producing pulses > by the use of differential amplifiers or comparators, with internal or external positive feedback

Circuits for generating electric pulses; Monostable, bistable or multistable circuits (H03K4/00 takes precedence; for digital function generators in computers G06F1/02) > Generators characterised by the type of circuit or by the means used for producing pulses (H03K3/64 - H03K3/84 take precedence) > by the use of differential amplifiers or comparators, with internal or external positive feedback