| 摘要 |
<p>PURPOSE:To make a protective diode unnecessary by using a field-effect transistor for the main part of a field voltage regulating circuit. CONSTITUTION:In immediately after the starting of a motor, the output voltage of an output coil 51 is low. For this reason, a controlling transistor 70 is cut off. The gate is supplied to FET 35 through an auxiliary coil 52 to the resistance 71 by cutting off of the controlling transistor 70, continuity of FET 35 is established and the current flows to the field coil 2. In case the output voltage is getting high, continuity of the transistor 70 is established and FET 35 is cut off so that the current does not flow to the field coil 2 and the output voltage lowers. Accordingly, something equivalent to diode characteristically is incorporated into the FET to be used so that it is not necessary to connect a protective diode newly.</p> |
