The Photovoltaic AC Relay (PVA) is a single-pole, normally open solid state replacement for electro-mechanical relays used for general purpose switching of analog signals. It utilizes as an output switch a unique bidirectional (AC or DC) MOSFET power IC termed a BOSFET. The BOSFET is controlled by a photovoltaic generator of novel construction, which is energized by radiation from a dielectrically isolated light emitting diode (LED). The PVA30 series combines very low solid state output capacitance, very high off-state resistance and very fast response. These Photovoltaic Relays are designed specifically to accurately switch low-level signals in high-performance instrumentation systems. The PVA overcomes the limitations of both conventional and reed electromechanical relays by offering the solid state advantages of long life, high operating speed, low pick-up power, bounce-free operation, low thermal voltages and miniaturization. These advantages allow product improvement and design innovations in many applications such as process control, multiplexing, telecommunications, automatic test equipment and data acquisition. The PVA30 series can switch analog signals from thermocouple level to 300 volts peak AC or DC polarity. Signal frequencies into the RF range are easily controlled and switching rates up to 25kHz are achievable. The extremely small thermally generated offset voltages allow increased measurement accuracies. The critical output semiconductors are completely shielded from the infra-red radiation of the input LED. Therefore, photocurrents in the output BOSFET are nonexistent and there is not an output offset resulting from radiation from the input LED drive.