The Time Electronics 1021 is a precision DC current source suitable for calibration and test applications from micro-amp levels up to 100mA. Three output ranges are available: 0 to 99.99mA in 10μA steps, 0 to 9.999mA in 1μA steps, and 0 to 999.9μA in 0.1μA steps. Output voltage is adjustable between 14 and 40 volts, with maximum output power of 2.4 watts .

The 1021 incorporates many proven features enabling fast and simple operation. An LED voltage limit indicator shows when the unit is unable to supply sufficient drive voltage to maintain the set output current. The instrument is short circuit and overload protected, and unique circuit design ensures it stays well within specification for at least 12 months. Variation with temperature is better than 60ppm per °C, typically better than 20ppm per hour at constant temperature .

A null measuring facility allows accurate DC current measurement by backing off the unknown current, with resolution of 1μA possible. This makes the 1021 suitable for both sourcing and measuring applications. To improve switch reliability, additional back-up contacts are used, ensuring continued operation even if a contact fails .

In the process industries, the 1021 can test and calibrate current-sensitive transducers and their associated indicating and recording instruments. The semiconductor industry requires constant current sources for parameter measurements, such as diode conduction voltages at specified current levels. The unit features safety terminals and is powered by NiMH rechargeable batteries with external mains recharge .