Abstract: A simulated ohms generating method and apparatus for calibrating electrical measuring instruments of the resistance and/or conductance measuring type are disclosed. First, the nature (current or voltage) of the internal power supply of the measuring instrument is determined by sequentially connecting two different resistors to the terminals of the instrument and determining if the current flow through the resistors changes (voltage source) or remains constant (current source). Depending upon the nature of the power supply one or the other of two sequences of steps are followed. While the sequences are somewhat different, they both include adjusting the output of a voltage source connected in series with a fixed resistor and applying the combination to the instrument to simulate a predetermined resistance (ohms) value. After this value is set, the instrument being calibrated is read to determine if the reading is the same as the predetermined resistance value being simulated.