Abstract: A defibrillator utilizes at least one flash tube for switching electrical energy from an energy source to a heart patient. The flash tube has a high impedance state in which the patient is isolated from the energy. In response to a triggering pulse, the flash tube enters a low impedance state in which energy is delivered to the patient. An additional switching element in the defibrillator operates to interrupt energy delivery through the flash tube so that a truncated defibrillation pulse having a desired energy level is produced.

Abstract: A pulse delivery control signal is applied to and removed from a master or pulse delivery electronic switch to respectively start and terminate the delivery of a trapezoidal waveform defibrillation pulse from charge storage capacitors to a patient. In one specific embodiment, a transfer charge storage circuit is coupled to a capacitor charging circuit for charging as the charge storage capacitors are charged. A transfer switch interconnects the transfer charge storage circuit to a first field-effect transistor switch. In response to a transfer signal, a transfer voltage signal is delivered from the transfer charge storage circuit, through the transfer switch and to the first field-effect transistor. In response, the first field-signal transistor applied the pulse delivery control signal to the master switch. A second field-effect transistor may be included for operating the master switch together with the first field-effect transistor.