A defibrillator combines a patient monitor with a controlled high-energy therapy system. It must acquire ECG, charge an energy-storage circuit, confirm conditions, route a waveform through supported electrodes, measure delivery, discharge safely, and document the event. Batteries and power management must support both monitoring and therapy readiness.

Key takeaways

  • The therapy capacitor is one element in a monitored charge-and-delivery chain.
  • Electrodes, cables, relays, switching, measurement, and waveform control affect delivered energy.
  • Battery capacity for ordinary monitoring does not by itself prove therapy readiness.

01

Charging and energy storage

A high-voltage converter charges one or more capacitors under control of voltage measurement and protective circuits. Bleeder and discharge paths manage stored energy when therapy is not delivered. Charging time can be influenced by the battery, power supply, converter, capacitor condition, temperature, and control state.

02

Therapy delivery path

High-energy switches, relays, waveform networks, internal paddles or external electrode cables, connectors, and supported pads form the delivery path. Biphasic waveform control and impedance-related behavior are device-specific. Damage or resistance in a cable or connector can affect the path without changing the user interface.

03

Monitoring, pacing, and controls

ECG acquisition, synchronization, external pacing, SpO₂ or other parameters, displays, recorders, audio, buttons, and event storage add separate modules and service boundaries. Therapy and monitoring can share electrodes or connectors while using different internal circuits.

04

Identification and verification

Identify the exact defibrillator family, therapy option, capacitor or therapy assembly, board revision, software, battery type, connector system, paddles or cable, and installed monitoring modules. Authorized testing generally includes charge time, delivered energy, synchronized operation, pacing where equipped, alarms, ECG, battery performance, and electrical safety.

Safety boundary

Defibrillators generate lethal voltage and store dangerous energy even after power is removed. Only trained personnel using manufacturer procedures and appropriate analyzers should open, service, or verify therapy circuitry.

Related terminology

Terms with a published definition link directly to the glossary.

defibrillatortherapy capacitorbiphasic waveformcardioversionexternal pacingenergy storage