A cartridge for a system that uses a stimulus signal for immobilizing a human or animal target includes a propellant and a projectile propelled away from about the cartridge by the propellant. The projectile includes a power supply, a waveform generator, and several electrodes. The waveform generator is powered by the power supply. The waveform generator includes a processor. The electrodes complete a stimulus delivery circuit to conduct a current through the target. The waveform generator generates the current to include a first series of pulses and a second series of pulses. The second series begins after the first series is completed. The first series has a first pulse repetition rate determined by the processor. Each pulse of the first series has a first pulse width of from about 10 to about 1000 microseconds. Each pulse of the first series delivers through the target a first charge per pulse of from about 50 to about 500 microcoulombs. The second series has a second pulse repetition rate determined by the processor to be less than the first pulse repetition rate. Each pulse of the second series delivers through the target a charge greater than a minimum charge per pulse. A product of the second pulse repetition rate and the minimum charge per pulse is greater than 250.