Abstract: A solid state safety relay comprises: a first driver circuit; a second driver circuit; a charge disconnect transistor coupled to the first driver circuit and configured to control the flow of current along a current path; a first discharge disconnect transistor coupled to the first driver circuit and configured to control the flow of current along the current path; and a second discharge disconnect transistor coupled to the second driver circuit and configured to control the flow of current along the current path. A method of isolating an energy source from a circuit current path, comprises: turning off a first discharge disconnect transistor coupled to the circuit current path; and turning off a second discharge disconnect transistor coupled to the circuit current path to permit isolation of the energy source from the circuit current path if either one of the first discharge disconnect transistor or the second discharge disconnect transistor fails.

Abstract: A power supply includes an inverter circuit comprising silicon controlled rectifiers which are driven by a variable frequency control signal. The frequency of the control signal is determined by monitoring the power output requirements of the power supply. Because of the continuous sinusoidal operation of the inverter, the supply generates a very low level of radio frequency interference (rfi).