Operating at just 1.35 V this circuit was found in a 1969 Electronic Design. The circuit makes use of transistors of the time but can be implemented with current equivalents.
This circuit was found in a 1967 General Electric documentation. The circuit generates signals...
We found this circuit in a 2004 documentation. The circuit consists of a standard lamp for testing...
Figure bellow shows another circuit that allows adjustments in the duty cycle of the output...