PIRA 5C30.20 - Capacitors: Short a Capacitor - A.K.A The Exploding
Photo Shows the Apparatus Used by the University of Texas at Austin.
Instructions / Notes:
- The short a capacitor demo uses a 400 microFarad capacitor - and - a 350 volt power supply that requires turning on multiple switches.
- To short the two terminals of the 400 microFarad capacitor, the demo office uses a fine # 30 gauge copper wire, which provides a pop sound to the demo.
Performing this Demonstration:
- To begin using this demo, turn-on the main power switch.
- Many faculty make two mistakes when preforming this demo.
- The first error is they fail to turn-on a bank of four switches on the rear of the power supply.
- This bank of secondary switches allow you to ramp up the voltage to 350 volts, without an excess of current at start up.
Photo # 2 shows the bank of secondary switches at the rear of the power supply.
- The second error sone faculty will make is to fail to remove the black wire prior to turning-off the main power switch.
- Disconnect the black wire by pulling gently.
- Turn-off the power supply via the main switch at the front.
- The Shield should by around the capacitor at all times.
- Short the capacitor by pushing down on the small copper wire, with
the provided discharge rod.
Photo # 3 shows the small copper wire.
- When installing the small copper wire - be sure to clean both ends of the wire with sand paper.
- One sanded end of the small copper wire should be wrapped around the negative post of the capacitor.
- Also, be sure to attach the alligator clip for the black wire to the negative post.
Update 9/16 - The University of Texas at Austin Physics Dept.
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