Abstract: A monitor for detecting failures in the installation of neon gas sign transformers has an electronic circuit in the transformer compartment to turn the transformer off in the event any failure occurs. The monitor uses a programmed digital micro-controller connected to the transformer and supplies an exciting current to a “TRIAC” that turns on/off the primary coil of the transformer under an AC voltage of the distribution network and also supplies a current to turn on a red LED when failures occur and a green LED that indicates if any power is being fed from the distribution network. When the sign lights properly, the TRIAC is activated, the transformer remains activated and the red LED remains inactivated while the green LED remains activated. When there is any failure the monitor detects the failure immediately and the transformer is turned off and six seconds later it is automatically turned on again. If the cause of the failure disappears, the transformer continues operating regularly.