2. Apparatus for starting and operating an arc discharge lamp having a starting peak voltage V1 and a normal operating voltage V2, where V1>V2, from a source of AC voltage having a half cycle time period of T seconds, comprising: electrical ballast means for presenting an electrical impedance to AC voltage, said ballast means including: a core of magnetic material; at least oNe winding located on said core, said winding comprising a predetermined plurality of turns of insulated electrical wire between a first and second winding end; and tap means on said winding located at a predetermined number of turns NT from said first winding end for dividing said winding into two winding portions, one portion being larger than the other portion, whereby the turns in said larger portion bears a ratio to the turns in said smaller portion, N-NT/NT, of greater than 1; arc discharge lamp means having first and second terminals; a circuit common of reference zero potential; means for connecting said second winding end in circuit with said first lamp terminal and means for connecting said second lamp terminal in circuit with said circuit common to place said winding and lamp in a series current conducting circuit; means for coupling AC voltages from an AC source into said one winding to provide an AC voltage V2 at said second winding end when said lamp is in a current conducting state and an AC voltage, V3, when said lamp is not in the current conducting state, where V1>V3>V2, and to provide an AC voltage at said tap means; first resistor means; first capacitor means; means connecting said first resistor means and said first capacitor means in electrical series circuit and means for connecting said electrical series circuit in circuit between said second winding end and said circuit common; unidirectional current conducting semiconductor controlled rectifier means having a positive polarity anode, a negative polarity cathode, and a gate electrode and having the characteristic of normally being in a noncurrent conducting state until triggered by a proper voltage at said gate electrode and thereupon conducting current only in a direction from its anode to its cathode, regardless of the maintenance of the proper voltage at said gate electrode, until such current reduces to zero and thereupon restoring to its non-current conducting state; unidirectional current diode rectifier means having a positive polarity terminal and a negative polarity terminal for conducting current therethrough only in a direction from its positive to negative terminals; second capacitor means; means connecting said second capacitor means and said semiconductor controlled rectifier means in a series current conducting circuit, including the anode and cathode thereof, and means locating said series circuit in circuit between said tap means and said circuit common; means connecting said diode rectifier means in circuit across said controlled rectifier means and with said diode means being poled in a direction opposite in polarity to the polarity of the respective controlled rectifier terminals so that said rectifier means conducts current only in a direction opposite to the direction of current conducted by said controlled rectifier means; diac semiconductor switch means responsive to a voltage of a predetermined level, V4, across its terminals for switching from a noncurrent conducting state to a current conducting state; second resistor means; means connecting said diac means and said second resistor means electrically in a series circuit with one end of said diac connected in circuit between said first resistor and first capacitor and with one end of said second resistor connected to said circuit common; and means connecting the gate electrode of said controlled rectifier means electrically in circuit between said diac switch means and said second resistor means, whereby responsive to said first capacitor charging to a voltage level, V4, said diac switches into a current conducting condition and applies a proper voltage from said capacitor to said gate electrode to trigger said controlled rectifier means into its current conducting state; said first resistance means and said first capacitance means being sized such that at said AC voltage, V3, applied to said first lamp terminal said first capacitor means is charged through said first resistor means to said voltage V4 within a time period of less than one-half cycle of AC and more than one-eighth cycle of AC but insufficient to attain said voltage V4 when the AC voltage at said first lamp terminal is of a level of V2 or less.