ESD zap

The DN2530 is a depletion-mode 300-volt nfet in SOT-89. It's good for about 3 watts dissipation if it's soldered to a chunk of copper foil, 1 watt maybe with a minimal pad. I have a graph of Id vs Rgs, current-limiter mode, if anybody wants it.

I've found the Supertex depletion fets to be very repeatable. The LND150 is always right around 1.6 mA Idss, which is handy for current limiting in lots of situations.

That should work for a channel or two. Here's hoping that your customer won't try this by applying 30V to a gazillion sensor ports simultaneously and then heading out to a place like Zeitgeist for an hour :-)

This will be a VME module, big power and ground planes, lots of air. It's going to be 16 channels. I'll certainly have to do the numbers before I have a final schematic, and I expect to be pummeled in a couple of design reviews, after which we'll go to Zeitgeist.

We'd have the design reviews at Zeitgeist, but our drawings would stick to those outdoor picnic tables.

Can't read the text, maybe it means "Do not run into this pole without a helmet?"

I got back into mountain biking a few months ago and sometimes you see scary stuff. Once it was some paint scrapings on rocks and chunks of the plastic covering from a helmet. Must have been a horrid wreck.

It's a Zeitgeist sticker! Bad photo, I admit.

At least on the ski slopes, the ski patrol (aka meat wagon) cleans up loose body parts quickly.

Aha! And I can guess who put it there. For those who don't know it:

On mountain trails a crash can have more serious consequences. Usually no cell connection so someone has to first find you, then ride out until the cell shows a signal to call for help. Help would probably arrive after a very long wait in the form of a stretcher that must be carried in and back out on foot. If it's really bad probably a helicopter but that may not work everywhere. Sometimes it's too late ...

One trip I made with the SF ski club, one of our guys took a wrong turn at the top of Alpine Meadows. They found him three days later, staggering around out of his mind, halfway to the lake. He was ultimately OK.

A few people die skiing, but not many per capita compared to, say, scuba or skydiving.

Heck, skiing isn't in the top 10.

Yup.

A few years ago, I was part of an amateur-radio team providing emergency-communcations radio support for a "back country" ride in the hills of Fort Ord in Monterey, CA. Cell coverage was terrible... and I'd found it necessary to build and carry along a portable 440 MHz Yagi antenna so that I could reach the event repeater system from the ridgetop where I was posted.

Saturday afternoon, as one batch of the riders were coming down a steep slope about a quarter-mile away, one guy lost control and was thrown and went unconscious after impact (he later said that he'd swerved to avoid another rider). The fire roads there were too rough to allow for safe transport by pickup truck, so we had to radio in for the med-evac 'copter from Santa Cruz and give them the GPS coordinates for the next hilltop over to land on.

The rider wanted to refuse transport ("I can't afford it") but the fire-and-rescue guys insisted. I later heard that bill was likely to run to well over $10,000. :-(

People generally don't remember much, if anything, that happened just before they were knocked out. He probably made that up.

The fire roads there were too rough

Another mistake, to refuse transport. He could have had a cerebral hemorrhage or something bad like that.

No, not me.

For those who don't know it:

Right under the 101 freeway. Real ambience.