Fail-Safe Circuits for Nuclear Protective Systems

The article describes a new set of fail-safe logic blocks particularly suited to safety systems. The input information is normally +5V; in case of alarm, the input drops to 0V. Fundamental blocks (AND, OR, NOT, etc.) are pulse-modulated, so as to achieve 0V output voltage in case of failure. More complex logic function can be synthesized and redundancy can be employed in order to avoid erroneous action.