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November 25, 2009
about 4 years ago
This is also why people are having issues with program corruption and sporadic operation. Sometimes the “stars line up” and you won’t have issues interfacing signals with grounds that are floating relative to each other. But eventually things will go bad. The reason pulsing the triacs eventually kills it is because there are various capacitances created by the various P-N junctions on the triac. Pulsing the traics is creating a AC drive signal that for all practical purposes, these capacitances are short circuits. If these caps are connected to a ground (HV Ground) that has floated lower then the MCU gnd, this is like connecting one of the pins of the MCU to -10…-12…-20V (I don’t know the exact value that it floats).
Unless I missed something, there is a major design flaw with this board. The HV ground of the traics is floating relative to the DC ground of the MCU. Essentially the HV ground can be higher and lower then the ground of the MCU. The “quick solution” at first might appear to be to tie these ground together……bad idea. The noise on the HV ground is going to be really bad. This is why the optocoupled triac drivers are needed. So in other words, this circuit needs to be scrapped.
about 5 years ago
What is the purpose of the numerous vias?
about 5 years ago
rsp: This is a nice arduino style concept demonstration kit, but not really much of a frequency counter.
For a more realistic (while still simple) frequency counter reference design, try this:
Ummm yea, I ordered that kit 9 months ago. Out of the box you had to use jumper wires because of a mistake with the PCB. I wasn’t surprised when pads started lifting during soldering. I emailed and complained. I was told I must have soldered it incorrectly - I work in a PCB fabrication and assembly shop. Made me pay for a replacement PCB. When I discovered the PIC included was lacking a program, I didn’t even bother to complain. Just chalked it up to getting ripped off.
News - Retail Packaging Has Arri…
about 6 years ago
SparkFun just went down a couple notches in my book. In my opinion, this kind of waste goes against the DIY mentality.
No public wish lists :(
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