Handbook 652 Body Electrical Diagnosis Current Current is the term used to describe the flow of electrons through the circuit. This flow of electrons does the “ work ” in the circuit. The unit for measuring the amount of current flow is the ampere or amp (A). One amp equals 628 billion billion electrons per second flowing through a circuit. Current will only flow if there is a complete circuit between a source of higher voltage (power) and a lower voltage (ground). Voltage is the pressure that pushes the electrons through the circuit and amperes are the measure of current flow. 26 Technical Training