Defibrillation is a treatment for life threatening cardiac dysrhythmias, specifically ventricular fibrillation and non perfusing ventricular tachycardia. A defibrillator delivers a dose of electric current (often called a counter shock) to the heart. This depolarizes a large amount of the heart muscle, ending the dysrhythmia. Subsequently, the body’s natural pacemaker in the sinoatrial node of the heart is able to re-establish normal sinus rhythm. Labtech Defibrillator Training Unit is designed to demonstrate the operation, theory, repair and servicing of Defibrillator equipment that used at clinics & hospitals. The unit is given the fault diagnosis so as to facilitate the teaching of trouble shooting techniques. A fault simulator is provided with circuit block diagram of the device for the students to study theoretically and experimentally in order to understand the operation of the device.