Additional circuit for infrared diodes

摘要

Once the energising current has been switched off, infrared diodes transmit light which is called afterglow and is produced by recombination of the charge carriers. This afterglow, which produces interferences in some applications, is prevented according to the invention in that an inductance is connected in parallel with the infrared diode or the series-connected infrared diode. The demagnetisation current of this inductance after the infrared diodes have been switched off clears out the charge carriers. In the case of a plurality of series-connected infrared diodes, a rectifier diode of opposite polarity must in each case be connected in parallel with each individual infrared diode in order to allow the demagnetisation current access to the infrared diodes which extinguish later, as well.