> -----Original Message----- > From: piclist-bounces@mit.edu On Behalf Of John Waters > Sent: Friday, May 26, 2006 12:02 AM > > 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 > > 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? A light turning off or on can create a large amount of electrical noise. The 4000 series CMOS logic family has very high input impedances making them very susceptible to noise pickup problems. Decreasing all circuit impedances will decrease the noise pickup problem. Do this by lowering all resistor values, raising all capacitor values and decreasing all wire lengths. If these simple fixes don't alleviate the problem you'll need to hook up an oscilloscope to see the noise and then figure out an effective shielding and filtering strategy. Paul > > Thanks in advanced! > > John -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist