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I need a simple closed electric circuit with only basic components: 9V battery; Simple on/off master switch; 3 LEDs: Blue, Red and Green; 2 variable controls: A and B; Fixed resistors; Other simple standard components if required. Expected behaviour when the master switch is on: Blue LED always on at fixed brightness; Increasing control A should direct current from green LED to red LED; Increasing control B should direct current back from red to green LED (overriding control A). Min A + Min B = Bright Green LED + Dim Red LED. Max A + Min B = Dim Green LED + Bright Red LED. Max A + Max B = Bright Green LED + Dim Red LED. Min A + Max B = Bright Green LED + Dim Red LED. |
July 25, 2026 |
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As it is, both switches are off, the LED is on. Close A but not B, the LED turns off. Close A and B, the LED turns on. Open A (as it is) and close B, the LED is on. Basically, it is the result of the logical expression: B OR (NOT A). Basically, that is the circuit for your GREEN LED. The circuit for your RED LED should be: A AND (NOT B) from what I understand. Using logical gates would produce a "neat" cut off, while working with resistors will only produce a somewhat not so clean behavior. Note that I haven't check the numerical value for the resistor. 9V to use LED is... very hight. |
by vanderghast July 29, 2026 |
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