This 1967 Motorola circuit is intended for operation with signals up to 250 MHz delivering a 50 MHz signal at the output. The transistor is the MM1941, uncommon today.
We find this circuit in an American publication of 1978. The integrated circuit is the CMOS 4013...
This circuit is a modification of the previous one, also found in the July 1995 Electronics Now...
This circuit was found in a 1968 EEE and can be implemented with any current general-purpose transistor....