Short-circuit protection for regulators

It is not always realized that, when a short-circuit occurs in a circuit supplied via a Type 78xx regulator, this and similar types of regulator can not suddenly cut off. When a short-circuit occurs a certain output current continues to flow. Although its level is limited, it can, nevertheless, cause damage in a few cases. This can be prevented with the present circuit, in which, when the output voltage of the regulator is too low, a bistable is actuated that instantly disconnects the Input voltage from the regulator via an electronlc switch.