Search Coils - Axial & Lateral. A search coil is used to measure field strengths and flux densities between the poles of electromagnets. Either an oscilloscope is connected to measure the induced voltages or AC or DC currents are passed through the coils to study the effects. The small coils have 5000 turns of very fine wire wound on them and they are mounted to circuit board strips for excellent strength and to bring the coil connections to the opposite end of the strip to 4mm sockets. Axial coil has the axis of the hole through the coil axial to the strip. The Lateral coil lies flat on the strip.