US 4,232,252 A · Lighting network including a gas discharge lamp and standby lamp

Abstract

A lighting network is described which includes a main gas discharge lamp, a standby lamp and a control circuit. The control circuit senses when the gas discharge lamp is operating normally and turns off the standby lamp. When the discharge lamp is not up to full light output after ignition or has gone out due to a momentary power interruption, the control circuit turns on the standby lamp. The control circuit includes a transistor amplitude discriminator and an electronic switch. The discriminator, which senses the voltage at the discharge lamp terminals, has a transfer characteristic which produces a "low" output over a "normal" range of terminal voltages and a "high" output for terminal voltages below and above the normal range. The electronic switch responds to "high" and "low" discriminator outputs to turn on or turn off the standby lamp, respectively. The discriminator is realized in its simplest form by a transistor amplifier comprising a junction transistor in the emitter common configuration with an emitter connected resistance. The voltages at the discharge lamp terminals are coupled to the transistor input junction through a step down transformer. The transformed voltages effect large signal operation of the transistor taking it through cut-off; the active region with inverting signal transfer and gain; and finally high current saturation in which a voltage drop is produced in the emitter resistance to achieve a non-inverting unity gain signal transfer to produce the respective high, low and high outputs. A preferred electronic switch is a silicon controlled rectifier for control of the standby lamp.

Claims15

Dependent claims

A lighting network comprising:

(a) a main gas discharge lamp having terminals for connection to a source of electrical energy, said main lamp having a low temperature ignited state with a low light output;
and an operating temperature ignited state with a normal light output,
(b) first power supply means coupled to said main lamp terminals for supplying an operating potential;
said lamp potential, when connected to said power supply means, being low at said low temperature ignited state and normal at said operating temperature ignited state,
(c) a standby lamp for use when said main lamp is below normal light output,
(d) a second power supply means for operating said standby lamp, and
(e) control means including:
(1) an amplitude discriminator comprising a transistor amplifier exhibiting cut-off at a low input range and active operation with input inversion at a higher input range to effect a transfer characteristic in which electrical inputs in said low and higher ranges respectively, produce an output quantity in respectively a first range and a second range distinct from said first range,
(2) means coupling a voltage proportional to said main lamp voltage to said discriminator to effect amplifier cut-off when said main lamp is in the low voltage, low temperature ignited state, and active input inversion when said main lamp is in the normal voltage, operating temperature ignited state, and
(3) switching means coupled to the output of said discriminator for applying power from said first power supply means to said standby lamp for amplitude discriminator outputs in said first range and for removing power for outputs in said second range.

7 more elements

A lighting network comprising:

(a) a main gas discharge lamp having terminals for connection to a source of electrical energy, said main lamp having an off state, a low temperature ignited state with a low light output, and an operating temperature ignited state with a normal light output,
(b) first power supply means coupled to said main lamp terminals for supplying an operating potential;
said lamp potential, when connected to said power supply means, being low at said low temperature ignited state, normal at said operating temperature ignited state, and elevated above normal when said lamp is off,
(c) a standby lamp for use when said main lamp is below normal light output,
(d) second power supply means for operating said standby lamp, and
(e) control means including:
(1) an amplitude discriminator comprising a transistor amplifier exhibiting cut-off at a low input range;
active operation with input inversion at an intermediate input range;
and an uninverted input transfer at a high input range to effect a transfer characteristic in which electrical inputs in said low, intermediate and high ranges respectively produce an output quantity in respectively a first range, a second range distinct from the first range, and said first range,
(2) means coupling a voltage proportional to the voltage across said main lamp to said discriminator to effect cut-off when said main lamp is in the low voltage, low temperature ignited state;
active input inversion when said main lamp is in the normal voltage, operating temperature ignited state;
and an uninverted input transfer when said main lamp is off and has an elevated voltage, and
(3) switching means coupled to the output of said discriminator for applying power from said power supply means to said standby lamp for amplitude discriminator outputs in said first range and for removing power for outputs in said second range.

10 more elements

Dependencies are inferred from the claim text.

Lighting network including a gas discharge lamp and standby lamp

Life of this patent

Lighting network including a gas discharge lamp and standby lamp

Life of this patent

Abstract

Claims15