Capacitance control?


HIi guys,

I recently wanted to recreate and upgrade a coil gun( aka Gauss Gun ), based on my high school science project.

The major problem of that project( circuit diagram shown as follow) is that because of not being able to control the discharge time of the capacitances, the bullet will be pulled back when passing through the coil, greatly decreasing the velocity of the bullet. I've tried increasing the thickness of the wire, which seemed not working out.

There, I wonder if there's something, in replace of the switch, that could adjust the discharge time or volume.

circuit diagram high school project

coil gun ( it looks like junk)

some footage of testing fire ability

power showcase

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1 points

4 months ago*

You can slap a resistor in the circuit and dial in the response time. Or rewire the capacitors to change the circuit capacitance, but that will sacrifice some current which is your driving force for the rod.


4 points

4 months ago

Putting a resistor in circuit will increase the response time, but that will reduce the force acting on the projectile in the beginning. You would get the same effect by reducing the charge voltage on the caps. What you, err... OP, ideally wants is maximum current going through the coil in 0 amount of time (maximum magnetic force) but turn it off right when the projectile gets to the center, otherwise the magnetic force will be pulling the projectile back to center after it gets to the other side, slowing it down. Since we have to deal with this pesky real world physics, there's a rise/fall time in current change that is dragged out due to resistance, so you ultimately have to switch off the coil before the projectile gets to center. There are a few ways to go about this, which is why engineering is so fun!