Abstract: An electronic ballast circuit for operating an unlimited number of fluorescent lamps, which provides a high frequency, high open circuit voltage to start almost any fluorescent lamp and a constant current to the lamps once they are started. A single ballast is designed and rated to operate over a power range, simultaneously supplying a number of lamps. The ballast receives 120 VAC or higher voltage, 50 Hz/60 Hz input power, converts the AC input to a high voltage, high frequency sine wave voltage output to fluorescent lamps connected in series or parallel. One or more selected output capacitors provide current limiting to the lamps, which extends their life by reducing stress. The ballast includes a unique starter circuit that is simple, reliable and low in losses as compared with conventional ballasts.

Abstract: A low cost multipurpose electronic ballast for ultraviolet transilluminators and crosslinkers for starting and operating four or more ultraviolet lamps simultaneously. The electronic ballast is designed to be capable of operating with input voltages ranging from 85 volts AC to 250 volts AC and input frequencies ranging from 40 Hertz to 400 Hertz. The output to the lamps comes from a group of capacitors which control the current to the lamps. Because the output comes from capacitive ballasts in parallel, alternate sets of capacitors can be switched to alternate sets of lamps allowing the central ballast control to be used with different sets of lamps. By placing another set of capacitors in parallel with the existing output capacitors and making a momentary connection, a momentary power boost can be achieved. This feature also allows a variable intensity control comprised of a number of different size capacitors in series with the parallel group to vary the total current to all the lamps.

Abstract: A circuit for controlling low wattage gas discharge lamps comprised of a inductive coupling device, e.g., a transformer, a switching transistor, a current sensor, a comparator receiving a signal from the current sensor and driving the switching transistor, and a protective clamp circuit. The primary winding of the inductive coupling device receives a DC voltage and is also connected to the transistor. The transistor allows current to flow through the primary winding causing energy to be stored therein until the current sensor signals the comparator that a first threshold has been reached, the comparator then turns the switching transistor off and the inductive coupling device then enter a fly-back mode where the stored energy is applied to the lamp for a set period of time. The transistor then turns back on and this process is repeated so that the lamp receives a high frequency alternating voltage.

Abstract: A gas discharge lamp is connected across a step down auto transformer and in series with a solid state switching device and a resistor, and this combination is connected across a rectified AC voltage source. This switching device is controlled by a monostable multivibrator, the input of which is connected to the output of a comparator amplifier sensing the difference between the voltage drop across the above-mentioned resistor and a voltage which may be selected to vary light intensity. A starter aid conductor is placed adjacent the lamp and connected to the grounded side of the voltage source. This results in an efficient, high frequency operation of the lamp wherein the voltage gradient inside the lamp during starting ignition of the lamp is greatly increased to facilitate ignition despite the presence of the step down auto transformer, thereby permitting a decrease in the minimum fly back voltage necessary to start the lamp. As a result, reliability is increased.

Abstract: A gas discharge lamp is connected in parallel with an inductor and in series with a solid state switching device and a resistor, and this combination is connected across a rectified AC voltage source. This switching device is controlled by a monostable multivibrator, the input of which is connected to the output of a comparator amplifier sensing the difference between the voltage drop across the above-mentioned resistor and a voltage which bears a predetermined relationship to the rectified AC signal of said source. This results in a high frequency operation of the lamp wherein the lamp current level is controlled or modulated in accordance with the rectified AC supply voltage, providing a high power factor lamp circuit without the normal heavy lamp ballast. In addition, a circuit is disclosed which prohibits the lamp from exhibiting a high resistance when the AC voltage is at a zero crossing point, protecting the solid state switching device and stabilizing the high frequency.

Abstract: A gas discharge lamp is connected in parallel with an inductor and in series with a solid state switching device and a resistor, and this combination is connected across a DC voltage. This switching device is controlled by a monostable multivibrator, the input of which is connected to the output of a comparator amplifier sensing the difference between the voltage drop across the above mentioned resistor and the voltage of a variable reference voltage source.When the current through the inductor has increased to a point where the voltage drop across the resistor exceeds the voltage of the reference source, the comparator amplifier triggers the monostable multivibrator causing the solid state switching device to be turned off. This acts to collapse the magnetic field in the inductor thereby causing a large voltage to appear across the gas discharge lamp sufficient to light the lamp.