Blinking an LED s l o w l y
I get an email from Nuts and Volts magazine weekly with some links to free articles (see the newsletter signup link at the bottom of the page): https://www.nutsvolts.com/ This article caught my eye recently: https://www.nutsvolts.com/magazine/article/some-simple-transistor-and-ic-circuits Here is the web site of the author, KE3FL: https://www.cs.yrex.com/ke3fl/ The circuit that interested me was ramping the brightness of an LED up and down slowly to blink it. I finally read the article, the circuit is a phase shift oscillator but at less than 1 Hz so the caps are big (electrolytics). The author's video looks good although it's in subdued light. I had a little trouble getting the circuit to play (didn't have a white LED at hand) so I tried simulating it with LTSpice: the green trace is out, the blue trace is sine this is the collector voltage Since it does seem to simulate I tried fiddling with it - got it to sustain oscillation by increasing the series res...