NOR gate S-R latch
The description of this circuit can be found in Lessons in Electric Circuits: Volume VI - Experiments book, page 337.
Note: The supply voltage of ICs was changed from the original value to increase LED currents. Moreover, the output capacitances of these ICs were increased from their default values to improve the circuit's stability at the chosen frequency.
Note: The original switches were replaced by pulse sources, as by toggling switches we would restart the simulation neglecting previous state of the circuit.