the present invention provides , in one embodiment , a gas discharge lamp ballast with an integral shutdown timer . the ballast includes a circuit for receiving ac power , a converter circuit for converting the ac power to dc power and a square wave oscillator powered from the dc power . a resonant circuit powered by the square wave oscillator supplies power to at least one gas discharge lamp . a time - delay circuit disables the square wave oscillator , without interrupting the dc power supplied to the oscillator , upon the passage of a predetermined period of time from power - up of the ac power . the ballast can be realized with only a marginal increase in cost and size of the ballast .