Abstract: A bi-level ballast network is disclosed for operating an HID lamp at either a low power or standby level and at a high power or full light level. The network includes an unswitched capacitor connected to the transformer ballast coil and a switched capacitor connected to a solid state relay (SSR) circuit, the electronic components providing the switching therein being back-to-back SCR's. When the SSR is operated the contacts connected to the switched capacitor open or close at the next subsequent zero crossing of the applied ac source voltage. This changes the capacitance of the network to increase the power to the lamp or decrease the power thereto depending on the operating condition prior to the SSR being operated. Current, voltage and dvdt protection devices are also provided.

Abstract: A hinged bracket for permitting the swinging away, within limits, of at least one socket to permit easy access to an elongated, doubled-ended bulb for relamping purposes, the relamping apparatus holding the bulb firmly enough to prevent its dropping out of the sockets. The sockets are each spring-loaded and partly biased against the bulb in the open relamp position and firmly biased against the bulb in the position of use. A heat sink is also provided via a sleeve extension on the socket and a mating hump on the door which provides access, when removed, to one of the bulb sockets through relatively small openings in the fixture and the nearby reflector. The swinging away of the socket to one side of these openings provides easy access to the bulb that would not otherwise be possible.

Abstract: A lamp dimmer suited for fluorescent and other lamps which controllably notches the applied voltage to a lamp circuit each half cycle. Progressively larger dimming control voltages produces progressively wider notches as well as progressively causing the notches to be further from the zero-crossing occurrence toward the peak occurrence of the half cycles, thereby providing means for varying power to the light circuit. Optocoupler means is employed with respect to a power output bridge to isolate the control circuit from the power output circuit to the lamp. A photosensor used to sense the ambient light conditions is used to produce the dimming control voltage so as to achieve a balancing effect between the ambient and the artificial light produced by the lamp.

Abstract: A dc-to-ac inverter employing a control low power section and a power section. The low power section comprises a square wave generator, cross-coupled NOR latches and low level transistor switches for providing switching current to the power section. The power section employs complementary FET drivers and power switches connected to a battery or other source of dc and a ferro-resonant transformer for changing dc to ac.The power section is protected by a voltage sensor. In a preferred embodiment, this voltage is proportional to the current through the respective power switches and is used to unlatch the applicable NOR latch, thereby causing shut off of the protected network of the power section.

Abstract: A battery charger with an SCR providing high charging current to a battery until a predetermined high voltage level is sensed. When the voltage sensed reduces to a float voltage minimum level, a trickle charge current is supplied through another SCR until a float voltage maximum level is sensed, which suspends trickle charge current until the voltage again reduces to the float voltage minimum level. When a load reduces the battery voltage so that the sensed voltage is reduced to a predetermined low level below the float voltage minimum level, then the high charging current SCR is again gated on to charge the battery.

Abstract: An HPS starting aid for providing pulses to an HPS lamp via a ballast tap connection, the aid employing a capacitive voltage divider connected to the power distribution line for charging purposes. There is no power resistor so that the pulse width and amplitude is not dependent on voltage amplitude fluctuations of the line voltage. A voltage breakdown device and a timing RC network determine the pulse positioning of the starting pulse. The size of the capacitors in the capacitive voltage divider and the number of turns on the ballast tap winding determine the pulse width and amplitude.