<prompt> Range of current used by biphasic defibrillator30-100 joules100-300 joules300-1000 joules1000-2000 joules  <response>: Modern units deliver a biphasic shock, during which shock polarity is reversed mid-shock. This reduces the total energy required to depolarise the hea. The energy of first and second shocks should be 150joules and thereafter up to 200joules. Reference Harrison 20th edition pg 1576 