| 摘要 |
<p>PURPOSE:To obtain desired gradations with a simple circuit construction, by supplying each LED with a current at a level according to the gradation. CONSTITUTION:Each of IC circuits 2-0, 2-1, 2-2 is constituted of an IC circuit having a constant voltage source. For weighting the outputs of the IC circuits, a high resistance element having a resistance 4R is connected to each output terminal of the IC circuit 2-0 to supply a constant current at a level '1', whereas a high resistance element having a resistance 2R is connected to each output terminal of the IC circuit 2-1 to supply a constant current at a level '2', and a high resistance element having a resistance R is connected to each output terminal of the IC circuit 2-2 to supply a constant current at a level '1'. As a result, an LED 1-n is supplied with a current of a total level of '2', an LED 1-(n-1) is supplied with a current of a total level of '5', and so on.</p> |
