One AED is certified with a ratio of 1:10. According to the query related information, the ratio of obtaining a certificate for an AED is calculated based on the ratio of 1:10 for each machine. AED generally refers to automated external defibrillator. Automatic external defibrillator, also known as automatic external shock device, automatic electric shock device, automatic defibrillator, cardiac defibrillator and fool electric shock device, is a portable medical device that can diagnose specific arrhythmias and deliver electric shocks. Defibrillation is a medical device that can be used by non-professionals to rescue cardiac arrest patients.