This oxygen Sensor simulator is built from a 555 and few other common parts. Just when I thought I'd seen all the uses for the 555. The oxygen sensor on a cars exhaust is used to determine how efficiently the fuel mixture is to an engine.
The oxygen sensor simulator as built on a protoboard. Note the cigarette lighter plug used for power source. The adjustment knob is at the left, and the switch is on the right. The red indicator LED is in the middle. Only use red, because the voltage drop of the LED is part of the circuit!
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