This is an integrated clock circuit from the time and was published in the November 173 Radio Electronics magazine. The circuit uses an AE7218 as a base for restorers.
We find this circuit in an American 80's documentation. It makes use of IC sensor which is mounted...
This is a configuration obtained from an old manual, using an operational amplifier of the time....
In the figure we have the way to add hysteresis to an operational amplifier. The relationship...