| 摘要 |
<p>PURPOSE:To simplify the constitution of automatic detection and switching and to improve the practicality, by using the switching operation of an LED itself for displaying the type of tape and diode. CONSTITUTION:A reproducing equalizer, a recording equalizer and a recording bias current are switched by a voltage at other ends of leaf switches 4a, 4b. The bias current is switched by a voltage applied to a bias current generating section 73 and the bias current changes proportional to a supply voltage thereof. The supply voltage is controlled with a transistor (TR) 72 and equals to a base voltage thereof, then a resistance value fed between the base and ground is switched to a resistor 79 for a metal tape loading, a parallel resistance of resistors 79, 77 at chromium tape loading, and a parallel resistance of resistors 79, 77, 75 for normal tape loading respectively. The recording equalizer is switched with an FET91 and TRs 86, 80, and the reproducing equalizer is switched by an FET92.</p> |
