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12 Jan 2011
Using the 4001 quad nor gate CMOS IC and a few other basic parts, build this simple alternating LED flasher.
How to make an alternating LED flasher – [Link]
One Response to “How to make an alternating LED flasher”
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January 12th, 2011 at 6:38 pm
This is another instructable that is designed by somebody who knows nothing about electronics.
1) The timing capacitor is a polarized electrolytic type which is wrong because it has AC across it, not DC. So its polarity is backwards half the time.
The value of the timing resistor should be increased 10 times so this capacitor can be a 1uF film type.
2) Two gates in the IC are not used and should be properly disabled by connecting their inputs to ground.
3) An important supply bypass capacitor is missing.