What is a Pulse Discharge Capacitor? A pulse discharge capacitor is a device that is designed to store energy and release it in a very short duration. The energy stored in the capacitor is equal to half the rated capacitance times the voltage squared as shown here in this equation. The duration of the discharge pulse can be as low as 100ns depending on circuit conditions such as inductance, resistance, and other series components. For example, copper traces leading up to the discharge capacitor can increase the inductance of the circuit creating longer pulse times and lower currents. A resistor in series with the discharge capacitor increases the resistance of the circuit also creating longer pulse times and lower currents. Releasing energy in these short durations produces very high dV/dT (“D V D T”) and currents which can damage a typical capacitor. Pulse Discharge capacitors are designed using very robust dielectric material as well as internal construction making it suitable for very high currents as can be seen in the graph. In this example, a 4540, 100nF capacitor is reaching peak current of 2,050 A in just under 400ns.