Abstract: Emergency lighting with a charging indicator circuitry comprises a power source module, a lighting circuit, a battery circuit, and an emergency switch circuit. The battery circuit includes charging indicator circuitry and a battery module; the power source module is connected with the battery module via the charging indicator circuitry. When the utility power is interrupted or a test switch is pressed, the light of the charging indicator circuitry goes out to indicate that the emergency lighting is in discharging status. When the utility power is supplied normally, if a battery within the battery module is in disconnected state, the light of the indicating circuitry goes out to indicate that the emergency lighting is in disconnected state. The charging indicator circuitry may be a simple light-emitting indicating circuit, has no need for much modification to the original circuit during manufacture and design, and may be simple and quickly-responsive.

Abstract: Structurally simple transmit/receive circuits for hearing devices are to be able to be deployed for higher frequencies as well. It is therefore proposed according to the invention that at least two PIN diodes should be connected in an anti-parallel manner between the receive oscillating circuit and the amplifier connected thereto to protect the amplifier. A capacitance diode can optionally be expanded so that larger component tolerances can be permitted for the circuit.

Abstract: There is provided a headphone with a behind-the-head headband comprising at least one transducer and a behind-the-head headband for receiving the transducer. The behind-the-head headband further comprises first and second contact locations for resting against a temporal bone of a wearer of the headphone. The spacing between the transducer and the first or second contact location can be adjusted. By virtue of the possibility of adjusting the spacing with respect to the contact location the transducer can be positioned exactly over the auditory channel of the headphone wearer without pressure points on the ear.

Abstract: An infrared emitter comprises a preamplifier, an infrared RF emitter, an infrared channel controller and a photodiode emitting-medium. With the emitter, by switching between two channels with an infrared channel controller, and by the mode of arrangement of a plurality of infrared emitting diodes and two Darlington amplifying circuits on the parts in a photodiode emitting-medium, crosstalk disturbance during transmitting carrier waves to a wireless earphone is inhibited. The emitter is applied to industries of audio/video playing, car audio/video equipment and hi-fi equipment.