Fifty Farads

Supercapacitors are polarized devices and must be connected with correct polarity. Reverse voltage can cause capacitor failure, overheating, or in extreme cases, venting of electrolyte. Always verify positive and negative terminals before applying voltage.

Never exceed the capacitor's rated voltage (typically 2.5-2.7V for 50F supercapacitors). Overvoltage can cause permanent damage or failure. Set your power supply to a safe value and verify it before charging.

Purpose

A 50-farad supercapacitor charged to 2.5 V stores ~156 J — enough to run a toy oil rig for up to 50 minutes. The rig pumps vigorously at first and slows progressively, giving students a visceral demonstration of $U = \frac{1}{2}CV^2$ and exponential RC discharge.

Xantrex power supply displaying 1.5 V and 1.0 A, connected to a black cylindrical supercapacitor in a test tube clamp on a ring stand, SPDT knife switch on a board with copper terminals, and a brass toy oil rig on a wooden base

Same setup with power supply display off, SPDT switch flipped to discharge position, oil rig in motion (slight blur visible on the pump arm)

Figure 1: Charging configuration: Xantrex power supply, 50 F supercapacitor in test tube clamp, SPDT knife switch, and brass toy oil rig.

Figure 2: Discharge mode: the switch connects the capacitor to the oil rig. The power supply is off to avoid the appearance of an additional energy source.

Warning: Polarity Warning

Warning: Voltage Limit

Purpose

Safety Warnings

Warning: Polarity Warning

Warning: Voltage Limit

Purpose