The Time Electronics 1024 is a precision DC current calibrator designed for calibration and test applications from nanoamp levels to 100 mA. This solid-state, battery-powered instrument is easily portable and convenient for laboratory, field, or industrial use, incorporating proven circuit techniques from the Time Electronics 1010 DC voltage calibrator.

The 1024 provides output in five ranges: 0-99.999mA (1μA steps), 0-9.9999mA (100nA steps), 0-999.99μA (10nA steps), 0-99.999μA (1nA steps), and 0-9.9999μA (0.1nA steps). Accuracy is ±0.02% of setting ±0.005% of range ±0.2nA, with output stability better than 10 ppm per hour at constant temperature and less than 30 ppm per °C over 0°C to 50°C. Drive voltage capability is up to 15V with new batteries or mains power.

A unique null balance system enables the 1024 to be used for accurate current measurement in addition to its function as a calibrator. Operation is achieved by backing the current source output against the current to be measured, with the difference displayed on a sensitive center-zone null meter. At the null point, there is no voltage drop across the 1024. Null sensitivity is adjustable from ±25mA to ±25μA full scale via front panel control, with maximum resolution of 0.5μA.

The 1024 employs a precision aged reference diode as the reference source, with excellent zero stability ensured by a high-performance FET chopper amplifier system. Precision metal film resistors with temperature coefficients of less than 10 ppm per °C maintain accuracy and stability. An LED indicator provides warning of insufficient drive voltage.

The instrument can be powered from mains supply or internal rechargeable battery pack, with full charge providing 12 hours typical use. Safety terminals are compatible with standard plugs, 4mm shrouded plugs, bare wires, and spade terminals. Applications include calibration of current-sensitive transducers, verification of digital and electronic current meters, and semiconductor measurements such as forward voltage drops and transistor gains.