There is provided herein a small form factor portable automatic external defibrillator (AED) having a controller, a charging circuit and a discharge circuit to discharge capacitors using a respective pair of electrode pads. The defibrillator may be separable into two portions at a bisection. Each portion may have a respective electrode pad on corresponding upper surfaces thereof for electrical contact with the chest. A circuit completion wire may complete the electric circuit between the two portions. The defibrillator may comprise a peel-off layer covering both adjacent electrodes. The peel-off layer is adhered to the board at peripheral edges thereof. As such, when pressure is applied to the bisection, the board snaps into the two portions and the peal of layer simultaneously peels from the portions. In this way, the defibrillator may be deployed quickly with a single break apart manoeuvre.