This circuit was obtained in an old Argentine publication, using germanium transistors and germanium diodes. The circuit can be adapted to operate with general purpose silicon transistors such as BC548 and BC558 for this with possible changes to resistors R5 and R6. The circuit is powered by a 6 to 9 V sinusoidal voltage that is converted into a square. The maximum frequency is in the order of a few kilohertz. The circuit operates as a trigger.
