end of tape detector

1... linear opamp which feeds a Schmitt trigger. In turn, the Schmitt trigger controls a so-called "totem-pole" output stage. Sensitivity to fluctuations in power supply levels is reduced considerably by the use of the Schmitt trigger. The totempole output enables the user to install several photo-detectors in parallel. Basically, this is how the circuit works: When the light beam is interrupted, the output of the photo- detector goes low and transistor T1 is turned off so possible around the heads and drive wheels before the break end of detector This design incorporates a new type of photo- detector which has a large number of applications such as detecting breaks in magnetic tapes. Before that the relay is deactivated. The normally closed contact of the relay keeps the motor of the tape player running. However, when something goes wrong, the beam from the transmitter (a Ga-As infra-red diode) reaches the receptor so that the output of the device goes high. This turns on transis...