Magn Pendulum Prototype.AVI

Prototype as indicated in Nuts & Volts Sept 2009. Coil made from magnet wire #29 (aprox 40 m long /14 OHMS). Dimensions ID 1/4", OD 1". Height 5/16" (9 mm).

Category:

Science & Technology

Tags:

• Electronics
• pendulum
• magnet
• transistors

[metracommm]

I'm the author of the article in Nut and Volts Magazine. Watching your green LED I can tell you that the biasing on the trigger transistor is not set correctly. The green LED should be off when the magnet is not moving. When the magnet swings over the coil the LED should turn on for less than a second. The magnet will swing higher and the battery will last longer this way also.

[enriquelaya]

@metracommm Many thanks for your comment. I corrected and improved the prototype thereafter. It took me a while as I was using a 2N 3906 instead of a NTE290A as you indicate (why are they that different?)...I will include shortly a video on a LEGO mounting prototype that makes it easier to try different lenghts, etc. Thanks again. enriquelaya

[metracommm]

The NTE290A provides more switching gain than the 2N23906.

[metracommm]

I'm the author of the article in Nut & Volts magazine. See my pendulum.