Monolithically integrable squarewave pulse generator

In a monolithically integrable squarewave pulse generator having a capacitor acted upon by two bucking constant-current sources, the capacitor having one terminal connected to the two constant-current sources as well as to a non-inverting input of an operational amplifier connected as a Scmitt trigger, and the capacitor having another terminal tied to reference potential, one of the constant-current sources being operative for charging the capacitor, the improvement comprising a third current source in the form of a transistor being normally off and having an electrode connected to the one capacitor terminal connected to the two constant-current sources and a base and an auxiliary voltage source connected to the base of the said third current source transistor for firing said third current source transistor during the discharge period of the capacitor because of the difference in potential between the base thereof and the capacitor, the Schmitt trigger having an output connected to signal output of the squarewave pulse generator.