| 摘要 |
<p>PURPOSE:To enable a load to be operated always in a normal condition by keeping a switching element in an off condition and feeding power to said load from another constant-voltage circuit at the time of the failure of a steady condition constant-voltage circuit, in a power source device for an automatic speed change control device. CONSTITUTION:Power from a storage battery 8 is fed to a microcomputer 1 via an ignition switch 7, a diode 14, a transistor 10, a constant-voltage circuit 5, and a transistor 3, while also being fed via a constant-voltage circuit 6 and a diode 9. The bias circuit of the constant-voltage circuit 5 consists of the transistor 10 and a capacitor 13, and the bias circuit of the transistor 3 as a switching element consists of resistances 4, 11 and a capacitor 12. Hence, if an ignition voltage is lowered failing to feed the voltage from the constant- voltage circuit 5 to the microcomputer 1, the transistor 3 is kept in an off condition and the voltage from the constant-voltage circuit 6 is fed to the computer 1 as the power source.</p> |
