A photovoltaic solid state relay has a light-emitting diode for emitting
light in response to an electrical control signal. First and second
photovoltaic devices are optically coupled to the light-emitting diode for
converting the light to first and second voltages, respectively. First and
second unipolar transistors are provided having first and second gate
electrodes for respectively receiving the first and second voltages and
jointly establishing a first current conducting path between output
terminals to which a load circuit will be connected. A bipolar transistor
is provided having a base connected to a junction between the first and
second unipolar transistors for establishing a second current conducting
path in parallel to the first current conducting path in one of opposite
directions depending on voltages applied to the output terminals.
