Abstract: Thermal switch assembly for photoelectric control device to switch loads such as street lighting luminaires on and off in response to ambient light levels. Housing having a portion integral with base of photocontrol unit and having a removable cap contains a bimetal relay assembly and positive temperature co-efficient resistor (PTCR) connected to a photocell for actuating the electrical contacts of the relay assembly.

Abstract: A linear direct current amplifier with automatic gain control system for regulating the peak-to-peak amplitude of the signal output that is acquired by scanning a coded label with a hand-held photo optical scanner is disclosed. The gain is set primarily by the white background on the coded label and it is further adjusted at the black bar as the pen passes over the label surface on which the code is imprinted. Control circuit feedback compensates for input amplitude and contrast variations.

Abstract: A wireless multiflashlight apparatus simultaneously illuminates a subject by flashlight rays emitted from a main flashlight device mounted on a photographic camera and at least one additional flashlight device located at suitable position away from the main flashlight device. In the main flashlight device is provided a flash tube arranged to emit substantially two or more flashlight rays at a predetermined time interval therebetween upon the shutter operation of an associated camera. In the additional flashlight device are provided a decoder for producing an outlet signal only upon receipt of the flashlight rays from the main flashlight device through a photo-electric conversion element and an amplifier, and a flash tube operative to be triggered only by the output signal from the decoder. The additional flashlight device is protected from inadvertently flashing even upon reception of any flashlight rays from other flashlight devices than the associated main flashlight device.

Abstract: A filter having a cut-off frequency of the order of 50Hz is included in the circuit of flame monitoring apparatus to remove signals below the cut-off frequency. In the circuit shown, a silicon p-n junction photo-electric pick-up is capacitively connected to an amplifier, the amplifier is connected to a high-pass filter, the output of the filter is connected to a further amplifier, the output of the further amplifier is applied to a detector integrator, the output of the detector integrator is connected to a Schmitt trigger, and the output of the trigger is applied to an output circuit giving a warning signal if the flame being monitored is extinguished. The use of sighting tubes for the photo-electric pick-ups is disclosed.

Abstract: In an optical switching system having a transmitter and a receiver optically coupled together via a fiber optic light guide, the transmitter utilizes a piezoelectric device which provides an electrical signal to a light emitting device when a mechanical strain is imparted to the piezoelectric device. The light emitted by the light source is provided at the receiver via the fiber optic guide. The receiver generates a signal in response to the light received thereat via the fiber optic guide. This generated signal is used to control the power flowing to a load via a switching device so that, for example, one generated signal is used to turn on the switching device and the next succeeding generated signal is used to turn off the switching device.