Is your power source bypassed at the chiip?
Are all inputs terminated in low impedance?  (Ground/Vdd)

John Waters wrote:

>Hi All,
>
>I encountered some strange problems when was doing experiments on a simple
>oscillator circuit. I built a circuit that was made up by the 4 COMS NOR
>gates in a CD4001. I used the first 2 NOR gates to build a simple monostable
>that turned on or off a low frequency oscillator made up by the 3rd and 4th
>NOR gates. The circuit was built on a breadboard, running on 6V batteries. I
>found the following strange things happened and could not explain why:-
>
>1. when I turned on my computer nearby, the frequency of the oscillator
>changed (slightly though). When I turned off the PC, the frequency went back
>to normal.
>
>2. I triggered the monostable manually so that the output went to the ON
>state, but when I switched the light in the room off, at that particular
>moment, the monostable went back to normal state automatically.
>
>It was obvious that my simple circuit was interfered, but I was using
>battery as the power source, there was no way the mains spikes could go to
>my circuit! Could somebody give an explaination and suggest how to make my
>circuit not susceptible to the interference?
>
>Thanks in advanced!
>
>John
>
>
>  
>

-- 
  *
  |  __O    Thomas C. Sefranek   WA1RHP@ARRL.net
  |_-\<,_   Amateur Radio Operator: WA1RHP  
  (*)/ (*)  Bicycle mobile on 145.41, 448.625 MHz

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