| 摘要 |
PURPOSE:To detect the traveling status of a recording medium at the time of recording, reproducing, quick feeding, and rewinding by detecting the difference of electric resistance on the surface of a magnetic tape by two sensors. CONSTITUTION:A bridge circuit consists of a resistor R1, a variable resistor R2, a power source E, a resistor 7 between electrodes 7a, 7b, and a resistor 8 between electrodes 8a, 8b. The bridge circuit is balanced when there is a magnetic tape having the same surface resistance between the electrodes 7a, 7b and between the electrodes 8a, 8b. If a reader tape on which any one of inter-electrode surface resistance is changed, the bridge circuit is unbalanced. Consequently a signal is outputted from a comparator 11 and a stop operation circuit 13 is actuated to stop the titled device. |
