Abstract: An ignitor disabler for disabling an ignitor in a high intensity discharge lamp monitors the operating or characteristic voltage of the lamp. When the characteristic voltage of the lamp exceeds an AC threshold established by the disabler, the ignitor disabler disables the ignitor to prevent spurious pulses. In this manner, the ignitor is effectively disabled during periods when the lamp is operating abnormally. The ignitor disabler includes a timing network which is reset only when an excessive voltage is detected. The reset portion of the disabler includes a field effect transistor for discharging the timing network.