4017 Traffic Lights
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This shows how traffic lights could be timed using a 4017 chip.
The diodes are being used as OR gates.
When output 0 is high, lamps A and F will be lit. Trace the wiring through the diodes to see why this is.
There are problems with this circuit though.
Here is a similar but simpler circuit that makes the letter "R" in Morse code.
The diodes provide the logical OR function so pins 0, 2, 3, 4 OR 6 activate the Morse buzzer.
For the Falstad Circuit Simulation, CTRL+Click Morse Code - Letter "r"
In options, check European Resistors and uncheck Conventional Current.
Alternatively view Morse_Code_R.txt.
Save or copy the text on the web page. Import the saved or copied text into the Falstad simulator.
Here is the new HTML5 Simulator Site.
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