| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a small-sized and low-priced constant current circuit which is easily manufactured.SOLUTION: A constant current circuit 1 includes: a first current path in which a current flows from one end of a resistor R1 to a resistor R4 and a collector and an emitter of a bipolar transistor 20 in order; and a second current path in which a current flows from the outside through an input terminal T1 to a collector and an emitter of a bipolar transistor 21 in order. In the second current path, a current that is a predetermined number multiple of the amount of the current flowing in the first current path flows. Regarding each of resistors R2 and R3, a microcomputer 10 adjusts a potential in one end or opens one end, thereby changing a quantity Iref of the current flowing in the first current path.</p> |
