Abstract: A circuit for monitoring a plurality of analog quantities which provides signals for exceeding of threshold values and utilizes a differential amplifier. One input of the differential amplifier is connected to a reference voltage source and the other input is connected to a reference resistor. The quantities to be monitored are represented by voltages or by impressed currents that are supplied to the input of the differential amplifier which is connected to the reference resistor and supplied thereto via decoupling diodes and coupling resistors. A plurality of coupling resistors are connected with reference resistor to form a single voltage divider whose taps receive the representative voltages or, impressed currents and are supplied in graduated steps according to values of the allocated threshold values.

Abstract: A circuit arrangement which permits interfacing logic systems operating on different logic levels and thus requiring different supply voltages in which the supply voltage for the logic system having the smaller signal excursion is obtained by means of a pair of zener diodes connected in series across the potential and reference potential of the logic system having a larger signal excursion to develop a potential and reference potential for the system having smaller signal excursions lying between the respective potential and reference potential levels of the system having larger excursions.