A plasma charge was a type of plasma weapon used as a hand-held or starship-mounted directed energy weapon discharge or as an explosive by various organizations, including Starfleet, the Bajoran resistance, the Miradorn the Son'a and the Turei.
During the Cardassian occupation of Bajor, Kira Nerys, as part of her role as a member of the Shakaar resistance cell, placed a plasma charge outside the bedroom window of Gul Pirak, a Cardassian occupier who executed fifteen Bajoran farmers for refusing to display the Cardassian banner outside their homes. The resultant explosion vaporized the entire east wing of Pirek's house, killing twelve Cardassians, including Pirak's family, and crippling twenty-three others. (DS9: "The Darkness and the Light")
In 2368, Ensign Ro Laren and Lieutenant Commander Geordi La Forge were able to hook up a modified laser scanner to a plasma inverter to fire a plasma charge in an attempt to incapacitate three Ux-Mal criminals who had taken over the bodies of Commander Data, Counselor Troi, and Chief O'Brien. The attempt was unsuccessful, however, as the entity in possession of Data's body left the plasma shock's range before they were able to fire. (TNG: "Power Play")
In 2369, the runabout Ganges came under attack by a Theta-class Miradorn vessel firing concentrated plasma charges, while Odo was using it to transport the criminal Croden to his homeworld of Rakhar in the Gamma Quadrant. (DS9: "Vortex")
In 2372, Chief O'Brien managed to rig a plasma charge while he and Doctor Bashir were being held captive by a group of rogue Jem'Hadar on a planet in the Gamma Quadrant. The charge was prematurely discovered, however, by a Jem'Hadar guard, forcing O'Brien to develop a new escape plan. (DS9: "Hippocratic Oath")
The same year, the USS Voyager came under attack by Turei plasma charges after taking shelter on the Vaadwaur homeworld. The Turei later redirected their charges towards the remnants of the Vaadwaur city, a number of Vaadwaur assault fighters, and the underground chamber where a group of Vaadwaur had survived for 900 years in stasis. (VOY: "Dragon's Teeth")