Millenium Bypass resistor question in "The Next Milleni

[Incubus]

In the pdf file titled "The Next Millenium" located at this link:

http://www.geofex.com/Article_Folders/Millenium/The%20Next%20Millenium.pdf

In figure 5, regarding the Millenium 2, there is a resistor in series with the control line. It's stated that its value can be anywhere from 1k to 10k, but that zero ohms works also.

In that picture, it's the first I've seen of that resistor.....any info about why it's there would be great.

[R.G.]

It's there to limit current through the diodes on the gate of the MOSFET.

If you ever should get a static electricity spark the control line, one or the other of the two diodes connected to the gate conduct and prevent the gate from getting fried. But the diodes are small signal types, with max one time currents of maybe a few amps. A really healthy static spark could kill the diode, the fry the gate. The resistor keeps the current down to something that will not kill the diodes.

As to why the tolerances are so loose: many people would NEVER have a static spark or other condition which would fry the gate. So it may not be needed at all. And since the one-time current of a diode is not a tightly defined parameter, putting something in there is as good a guess as putting in a highly-specified value.

Did that help?

[Incubus]

Helped much

Thank You.