A switching circuit includes a bridge rectifier to receive voltage inputs across a load and an optical isolator to receive a logic input signal and generate an output signal based on the logic input signal. The high speed switching circuit also includes a field effect transistor (FET) with a source connected to a negative output of the bridge rectifier, a drain connected to a positive output of the bridge rectifier through a second load, and a gate driven by the output signal of the optical isolator. First and second resistors connect the voltage inputs to the gate of the FET through first and second diodes. The first and second resistors and the first and second diodes limit current flowing to the gate of the FET. A Zener diode connected to the gate of the FET limits voltage to the gate of the FET below a maximum voltage rating of the FET.