Abstract: A ballistic comparative ohmmeter for use in testing the resistance between different selected pairs of a plurality of terminals in a test circuit in comparison to the resistance between corresponding pairs of terminals in a reference circuit. the ohmmeter is particularly useful for making resistance tests in circuits included in assembled products. The ohmmeter makes comparative resistance tests during a transient response period following application of the current to the selected pair of terminals as well as under steady state conditions. Solid state stepping switches that are sequentially stepped by pulse counters are utilized to sequentially connect different combinations of terminals in the test circuit and the reference circuit. Protection circuits limit the voltages applied across the test circuit and master circuit terminals. Indicator panels immediately provide a steady state indication of the pair of terminals in the test circuit at which a fault is detected.

Abstract: A circuit which performs regulator or limiter functions at current and voltage levels below the operating ranges of conventional zener diodes. The output of an op amp is connected through a diode to a main input terminal which may be connected between a power source and one end of a load resistor. A first current limiting resistor connects the main input terminal to the inverting input of the op amp. A second current limiting resistor connects the non-inverting input of the op amp to the wiper terminal of a potentiometer which permits adjustment of a simulated zener voltage V.sub.z. A pair of supply voltage terminals of the op amp are connected to voltages V.sub.cc and V.sub.ee, respectively. A pair of fixed terminals of the potentiometer are also connected to voltages V.sub.cc and V.sub.ee, respectively. The simulated zener voltage V.sub.z may be positive or negative, and may be adjusted to any value within limits determined by voltages V.sub.cc and V.sub.