| 摘要 |
PURPOSE:To obtain a constant current source by connecting in series a resistor equal to VGS1/ID the drain current and tha value at the intersection of the characteristic curves of the voltage between gate and source that are obtained when temperature is changed with the voltage between drain and source kept constant are ID and VGS1 respectively. CONSTITUTION:When ambient temperature is changed with the voltage between drain and source kept constant, the chracteristic curves of the drain current - voltage between gate and source intersect each other almost at a point (ID1, VGS1) and the variation of drain current by temperature is minimum at said point. By utilizing this, voltage VGS1 and current ID1 are maintained at self-saturation bias by a source resistance RS VGS1/ID1 at a source earthing type circuit. The N-epitaxial layer 2 on a P<+>-type substrate 1 is separated by P<+>-type layer 3. An FET 100 and a resistor layer 200 are provided on each of thus-obtained divisions of said layer 2, resistance value if formed at RS, and one-end N<+>-layer 9 is connected 10 to the N<+>-layer 5 of said FET 100, A constant current source can be obtained using N<+>- layer 8, N<+>-layer 6 and said sobstrate 1 as source, drain and gate respectively. |
