| 摘要 |
<p>PURPOSE:To prevent wrond recording by sending forth a failure signal by using a system in which the output voltage of switching elements for selecting each block is given to a signal adding element, and according to the number of block elements concurrently electrified, added electric signal is generated. CONSTITUTION:In case where a switching transistor TR1 for selecting blocks is not off, a period when two switching transistors TR1 and TR2 for selecting blocks turn on at the same time is generated, current flows concurrently from resistors R13 and R14 to a signal addition resistor R16, and added electric signal voltage generated at the poing (a) becomes greater than the reference voltage at the point (b). The output F of a comparator 7 becomes low, a filpflop 8 is reset, and the output G becomes low. Since the gate 6 is closed and electrification signal H does high, no current flows in the heating resistors 1-12, a recording stop circuit 10 is operated to stop recording, and the recording is displayed on a displayer 9.</p> |
