An Inexpensive High-Precision Constant-Current System with Metering Electronics

A precision constant-current supply designed to deliver up to 600 mA at 18 V dc is described. Short-term stability (<8 h) is within ±0.002 percent of range. Long-term stability (72 h) is ±0.01 percent of range. The system is discussed in relation to its application for the control of magnetic environments using a three-axis Helmholtz coil configuration.