A waveform generator in which the primary of a transformer includes a nonlinear network so that when a sinusoidal source is connected, there is a notch in the voltage waveform at the primary winding, the notch having a complex function. The same notch appears at the secondary winding and is fed through a further network to three floating terminals at relatively different direct current levels for use with oscilloscopes for testing and instructing.
An apparatus for monitoring phased currents in a first winding and a second winding of a transformer and for disconnecting the transformer from a power source supplying the transformer when a difference between the magnitude of the current in the first winding and the magnitude of the current in the second winding exceeds a predetermined amount to indicate a fault condition is disclosed. The apparatus is used in combination with circuitry for generating first and second current signals each having a phase and magnitude which is a function of the phase and magnitude of the phased currents in the first and second windings, respectively. The apparatus includes a circuit for shifting the phase of the second current signal to match the phase of the first current signal, a circuit for detecting a difference between the magnitude of the first current signal and the magnitude of the phase shifted second current signal, and a circuit for disconnecting the transformer from the power source when the detected difference exceeds the predetermiend amount.
