| 摘要 |
PURPOSE:To simplify a circuit constitution so as to reduce the cost, by disusing a varister and utilizing the forward voltage of a light emission diode as a stabilizing voltage. CONSTITUTION:A varister is disused and a recording head 1 and light emission diode D22 are connected with each other through a resistance R23. When an appropriate electric current is made to flow to the light emission diode D22 by means of the resistance R23, the voltage VF across both ends of the light emission diode D22 becomes a constant value even when a supply voltage Vcc varies to some extent. Therefore, a stabilized DC bias current IB can be supplied to the recording head 1 through the resistance R22. When such an arrangement is made, the circuit constitution can be simplified and the cost can be reduced. |
