this post was submitted on 29 Mar 2024
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Hello,

I'm creating a BoM for a youth group project. We're planning on building the Electromagnetic Ring Accelerator from Hyperspace Pirate. He's provided the 3d print files, but not the finer details on wire gauge, enamel wire gauge and ball size. I also want to confirm the photoresistor. Are there different photoresistors with with different sensitivities or ranges?

I've included the wip of the BoM.

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[–] renormalizer@feddit.de 1 points 7 months ago* (last edited 7 months ago)

IIRC, the first model ate mosfets for breakfast because the photo resistor is way too slow going from illuminated to dark. That leaves the mosfet in a fairly high resistance state for an extended amount of time during which it dissipates a lot of power. You should add some kind of Schmitt trigger inverter that buffers the resistive divider and gives you a clean narrow edge to drive the mosfet gate. A 74HC14 together with a 7805 voltage regulator should give you enough output voltage to drive the mosfet. These chips cost less than a single replacement mosfet and you can drive 6 coils with them.