| 摘要 |
<p>PURPOSE:To protect a lighting control circuit from overvoltage by restraining generation of an excessive voltage so as to form a load of a dynamo through a overvoltage detecting/current absorbing means when an electromotive voltage of the dynamo exceeds a predetermined value. CONSTITUTION:An output of a second comparator IC2 is connected to a positive side of an output line of a full wave rectifier through a forward direction Zener diode ZD1 and a resistance R5. When, for example, a lamp 3 is disconnected and a voltage between the positive and the negative output lines of the full wave rectifier exceeds a Zener voltage of the Zener diode ZD1, an electric current from the positive output line of the full wave rectifier is absorbed in the output of the second comparator IC2 through the resistance R5 and the Zener diode ZD1. In this way, as a new closed circuit is formed between the positive and the negative output lines of the full wave rectifier, the voltage between the positive and the negative output lines of the full wave rectifier is restrained, and an excessive current is not supplied to a coil of a relay RL.</p> |
