Search found 5 matches

by metracom
Thu Sep 17, 2009 8:36 pm
Forum: Projects & Kits
Topic: Magnetic Pendulum
Replies: 8
Views: 6435

Re: Magnetic Pendulum

mosimpson I'm glad to see that you and your son are enjoying the Magnetic Pendulum project. You will find that upholstery thread works better than fishing line. Fishing line will work, but with added drag. Remember the less drag the better. The arm on my pendulum is 8 inches long. There are lots of ...
by metracom
Thu Sep 03, 2009 5:04 am
Forum: Projects & Kits
Topic: Magnetic Pendulum
Replies: 8
Views: 6435

Re: Magnetic Pendulum

Dave, thanks for the additional pictures. If you use a NTE290A transistor will give you more pendulum arc. I tried connecting a cap on the base of Q1 but that caused the transistor to not switch properly. I think it shunts the feedback from the coil. Just solider a few unused circuit board traces to...
by metracom
Wed Sep 02, 2009 5:03 pm
Forum: Projects & Kits
Topic: Magnetic Pendulum
Replies: 8
Views: 6435

Re: Magnetic Pendulum

If you build a Magnetic Pendulum please take a video and post the link on this thread.

Here's my video. http://www.youtube.com/watch?v=4xTjIzzbXTQ

Tony
by metracom
Wed Sep 02, 2009 2:59 pm
Forum: Projects & Kits
Topic: Magnetic Pendulum
Replies: 8
Views: 6435

Re: Magnetic Pendulum

Dave, I'm glad to see your having with the pendulum !!

Tony Gasparovic :grin:
by metracom
Fri Aug 28, 2009 11:03 am
Forum: General Discussion
Topic: 30 second timer (LM555?)
Replies: 5
Views: 1077

Re: 30 second timer (LM555?)

What you need is a missing pulse detector circuit. This circuit can be constructed using a 555 chip, transistor and a couple of components to set the RC time constant. Do a search on goggle for "missing pulse detector" 555. I have built many many of these. The timer re-sets itself each time the swic...