Abstract: A method of measuring light intensity comprising exposing a photodiode to light to cause the photodiode to provide a current of a first polarity, supplying said current to an integrator to integrate said current to provide an integrated output voltage, and comparing the output voltage with a threshold voltage. Charge packages of opposite polarity are applied to said first polarity to reset the integration voltage prior to the start of the integration time. At the end of the integration time, the photodiode is disconnected from said integrator and a reference voltage coupled to the integrator input, whilst a resistance is coupled into the circuit until the comparison signal switches. The comparison signal is monitored to measure a time between the end of the integration time and the switching of the comparison signal to provide a measure of a residual voltage.

Abstract: In an apparatus (1) having an electroacoustic transducer (14) and having a printed circuit board (51) the electroacoustic transducer (14) has two terminal contact elements (36, 37) and the printed circuit board (51) has two mating contact elements (52, 53), which terminal contact elements (36, 37) have two terminal contact portions (38, 39) which are oriented parallel to the transducer axis (34) of the transducer (14) and which mating contact elements (52, 53) have two mating contact portions (56, 57) which are oriented parallel to the transducer axis (34), the terminal contact portions (38, 39) and the mating contact portions (56, 57) being held pairwise against each other in a direction transverse to the transducer axis (34) and thus forming at least parts of a retainer (72) with the aid of which the transducer (14) is secured to the printed circuit board (51).

Abstract: In an electroacoustic transducer (1) having a diaphragm (17) and a voice coil (16) connected to the diaphragm (17) in the area of the rear volume (HV) and cooperating with a magnet system (9), and including a substantially annular closing member (30) for closing the rear volume (HV), the closing member (30) has an annular body (38) and a ring projection (39), which projects obliquely from the annular body (38) along its entire circumference and is movable against spring action, at least one passage (34, 35, 36, 37) of the closing member (30), this passage having been provided in order to realize an acoustic friction between the rear volume (HV) and the acoustic free space surrounding the transducer (1), terminating in the annular contact surface (32) of the annular body (38), this annular contact surface extending transversely to the transducer axis (2).

Abstract: In an electroacoustic transducer (1) having a diaphragm (5), a partition wall (24) situated behind the diaphragm (5) and traversed by partition openings (25, 26, 7, 28 and 29, 30, 31, 32), and a mask (37) arranged adjacent the partition wall and provided with mask openings (38, 39, 40, 41) which can be made to coincide with different openings (25, 26, 27, 28 and 29, 30, 31, 32, respectively) in different positions of the partition wall (24) and the mask (37) relative to one another, the mask is simply formed by a flange (37) of a magnet-system pan (19) of the magnet system (16) of the transducer (1).