Tape cassette drive electronic control - has photoresistor in series with electromagnetic switch connected with transistor cct.

摘要

Tape drive and control system for a cassette is based on a circuit comprising a photoresistor (1) illuminated by a light source (2) which passes through a rotating interception disc (3). The photoresistor (1) is in series with an earthed resistor (4) and on the other side connected with a switch (5) supplied by the operational voltage (UB). The switch is further connected with the winding (6) of an electromagnet and with the collector of a transistor (7) which forms part of an electronic switch (8) actuated by a mechanical key (9). A further winding (10) is in parallel with the switch and the electromagnetic coil. A diode (16) is between the transistor (7) and photoresistor (1), to prevent short circuits.