Abstract: A starting and operating circuit for high pressure discharge lamps including a pair of input terminals for connection to an alternating current supply and a pair of output terminals for connection across the lamp. A ballast inductor is connected at its ends in series between one of the input terminals and one of the output terminals and a pulse generator is connected between the output terminals. The pulse generator comprises a non-linear capacitor (NLC) and a semiconductor bipolar thyristor (commonly known as a SIDAC) connected in series, the non-linear capacitor and bipolar thyristor being connected in parallel with the discharge lamp.

Abstract: A starter circuit for fluorescent discharge lamps having a high reignition voltage with respect to a peak open circuit voltage wherein a timing and triggering circuit is utilized to delay the application of a the lamp voltage to a starter until the relatively high reignition voltage has passed and a normal lamp operating condition is in effect.

Abstract: A method of operating a high intensity discharge lamp having a pair of electrodes hermetically sealed within an arc tube, the method comprising frequency modulation of a carrier waveform in the kilohertz range to provide a variable frequency AC output, and applying the AC output across the electrodes of the lamp to thereby operate the lamp in a manner which minimizes or avoids acoustic resonance effects within the arc tube. The circuit includes an inverter having a first input provided by a DC power source and a drive input coupled to a square wave carrier generator which is frequency modulated by a ramp generator. The resulting variable frequency AC output of the inverter is then coupled across the lamp electrodes.

Abstract: A fluorescent lamp has an extension base at one end thereof which contains an impedance to reduce current flow through the lamp. The length of the lamp plus extension base equals the length of a standard fluorescent lamp.

Abstract: A ballast tester contains a DC detector, a peak voltage detector and a third harmonic detector. The DC detector determines if the ballast being tested can produce a steady DC current and is, therefore, a lag ballast. The peak voltage detector can identify the ballast as a lead ballast, while the third harmonic detector can determine if a lead ballast contains a starting capacitor.