A security apparatus includes a mount and a sensor body with a socket recessed into the sensor body at a first angle from a functionality plane. A frequency sweep generator sweeps the frequency of the lamp inverter to a striking frequency corresponding to a striking lamp voltage and then maintains the striking frequency until the lamp strikes. The base bracket includes lateral projections that engage stop members in the tray which keep the tray in a rearward position. An input digital value is received and divided by a number N, producing a quotient and a residue.