The invention discloses a high speed switching solid state relay circuit with a switching section, a current limiting section and a voltage limiting section. The switching section comprises a bridge rectifier receiving the load voltage inputs, a MOSFET with a source connected to the negative voltage of the load through the bridge rectifier, a drain connected to the load voltage output, and a gate. The switching section further includes an isolator circuit comprising an optically-coupled LED. The isolator circuit is configured to receive a logic input signal and generate an isolated output signal based on the logic input signal, and the gate of the MOSFET is driven by the isolated output signal. The current limiting section includes a first set of resistors connecting the voltage drop across the load to the gate of the MOSFET through diodes. The voltage limiting section comprises a Zener diode connected to the gate of the MOSFET.
