I may be able to help with some of your questions. (numbers from picture)



4) any 12 volt regulator should work. It is only driving the fan and LED, so just make sure it can handle the amps your fan requires.

5) The LED is only to show the unit is on, so any kind of LED would work.

6) Not sure the values of the resistors - Seems like 1k ohm would be better. I say this because the resistor in series with the LED (at 12 volts) would need to be higher than 220 ohms, more like the 1k ohm range. I would bet it is supposed to be 1k.

7) any fan will work. Just make sure it is big enough (if stuff starts getting too hot, smelling bad or letting smoke out, its not big enough) and you can hook it to 12 volts and make it work.

9) These are standard standoffs, meant to support PCBs above a base. They are being used here as connectors, not their intended purpose. They are metal and tall enough that you can connect the thick wire to easily. The exact measurements are not needed. Use what you can find, or use a different type of connector that you are familiar with that can handle large amperage.

11) 1N821 vs 1N821A - they are the same zener diode, only the "A" version is 10 ohms where the no-A version is 15. Either should work, I would think.

12) Not sure, I didn't catch what henrys the inductor was.

13) The exact size and composition of the PCB doesn't affect how the device works. I would go for the cheapest option. Choose what is prettiest to you. Or make your own (that's what I do). Or use perf board. Or drill holes in thin plywood and then wire components up manually with wire under the plywood. Or plexiglass.



Hope this helps.

