tterrag t

I'm trying to provide a 4 mhz signal to my PIC 18f452. I've always used a 4 mhz clock, but thought I should move to using crystals since they're cheaper and smaller.

I wired up my crystal to the pic with two 20pf caps but my clock only sometimes works and when it does it never oscillates at the correct frequency. If I remove the capacitors the crystal creates an almost perfect 1khz sinusoid. I'm starting to wonder if the crystals I have might somehow have been mislabeled or is it possible for 4mhz crystals to also oscillate at 1khz and if so what am I doing wrong that's causing this?

I recently bought an old hp 54201A oscilloscope off of eBay. I've been playing around with it and I've found that even when I connect both my ground pin and the probe to ground I still get 600mv read (DC coupling) and about 300 mv (AC coupling). I've tried using the automatic calibration in the menu which helped a little but not much. It's not a big issue, and the scope is pretty darn old but if someone has a fix I'd really appreciate it.

So a few days ago I made a comment on a popular video. I just checked my youtube account and it has a notification in my inbox showing a reply to my comment. I can see the comment the replier posted in the message from youtube but there is no option to respond to it. Is there a way of doing that? Sifting through the comments on the video isn't an option since being a popular video it's been getting comments like crazy.

My club is holding a soldering workshop in two weeks. We're looking for something simple that participants can practice soldering with that will be something that they can hold onto. Ideas we've bounced around are an LED keychain, or something of the like. The idea is that we can teach the basics of soldering and the participants will have something to take with them when they leave. We don't have a large budget for the workshop so it should be something that is under $5 a person. Any ideas?

I recently got a great deal on a older projector on e-bay, and I'm trying to find the correct cable to connect my computer to it. Here's the rub, the projector has the VGA sized connector as a video output which is labeled RGB out, but the RGB in isn't the size of the VGA connector. The input has the correct amount of pins (15), but they're broken into two rows one of 8 and the other 7 (as opposed to three rows of 5 for standard VGA). I looked into it and it seems that this format is called DA-15 as opposed to the VGA connector which is DE-15. However, I'm having trouble finding a cable that converts between the two, so what is that cable called or where can I find it?

I'm able to get to the part where 2pi*Integral(sqrt(64e^(5y)+e^y)) but i can't get past this point since the normal identity I use requires one term to be a constant.

I was just wondering if you could get similar results from taking say 4-5 1-2 hour naps during the day instead of sleeping for 8 hours in a block?