On 02/22/2012 07:57 PM, Jim Brain wrote: > On 2/16/2012 10:49 AM, Gerrit Heitsch wrote: >> >> D1 = 1N4148 > Why is D1 needed? In the reverse mode, the optocouple won't conduct, so > they're no concerns. A LED can only take a very limited reverse voltage. The number I once learned was 5V, apply more and you might destroy it. The antiparallel 1N4148 limits the reverse voltage to 0.7V. >> C1 = 10 nF > I assume it's there to stretch the cycle. Given the 6.3V transformer > will have enough forward voltage for most of the half cycle, is the cap > really even needed? The idea with the cap was not to stretch the cycle but to filter out short voltage spikes (line noise). The value was a guess back then, but if you omit it, your clock will be fast (that part was tested). Gerrit Message was sent through the cbm-hackers mailing listReceived on 2012-02-22 20:00:26
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