I had a new design in my head: a trip-wire alarm, with time-out and reset, using five discrete components. It basically worked, but the time-out misbehaved. Going over it to find the fault, I see that it fell down on Zener diode reverse current -- one of the more obscure things that could go wrong. OBSERVATION: This is one of many examples where a theoretical circuit doesn't match the real world. It may mean that something doesn't work, or it may mean that one does some kind of harm which is not reckoned with (say, one's components blow out, or one even destroys a power supply or test equipment). One may compare this with the damage that theory does to the world today.
POSTSCRIPT: I created a Zener substitute, which requires 1% of the current of a typical Zener. Now it works, with six discrete components.
No comments:
Post a Comment