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John Wiltrout's Blog

September 2014 Previous month

A Lesson Learned

Posted by jw0752 Top Member Sep 25, 2014
This evening I was experimenting with a simple LM339 comparator circuit and a photo transistor. Everything appeared to be working fine but when I attempted to take some voltage readings with my Fluke 177 they were not what I expected. The inputs to the comparator were reading too high and acted as if there was voltage leakage from the inputs of the LM339. These input are very high impedance and there should be no leakage. The chip seemed to be working as it was sensing the change in voltage from ...
                                                                        Sometime in the mid 1960s I bought an EICO 1064 Battery Eliminator Power Supply ...

I Need an Extra Finger

Posted by jw0752 Top Member Sep 10, 2014
Since I retired a couple years ago I have returned to my life long interest in electronics. What I have discovered is that I had not kept up with the technology. The manageable, through the hole, components that I was familiar with in the past have been replaced by something that is very small and solders directly to the surface of the board. Not wanting to miss out on playing with some of these really neat goodies I decided to begin to acquaint myself with the components and the new techniques ...