This demonstration power supply unit is intended for use in educational institutions, laboratories and on production lines when carrying out experiments in electronics, electrical engineering and electric energy. It provides a regulated voltage from 0 to 30 volts and a current from 0 to 5 amperes and maintains high stability of voltage and current, and it is equipped with automatic switching between the modes of stabilised voltage and stabilised current, which allows different types of load to be connected without the risk of damage. Connection of the load is performed by the teacher or the laboratory assistant and pupils work under supervision; the recommended age of learners is from 10 years, that is pupils of grade 5 and above.
The output voltage is direct, stabilised and smoothly adjustable in the range from 0 to 30 V, and the output current range is from 0 to 5 A. The unit is powered from 180 to 230 V of alternating current with a rated tolerance of ±10 % at a frequency of 50 or 60 Hz. Voltage stability under load and with a change of the input voltage is 0.1 % + 10 mV, current stability is 0.1 % + 10 mA and 0.1 % + 20 mA under load, and the accuracy of the digital voltmeter and of the digital ammeter is ±0.1 % + 2. The front panel carries two four-digit LED displays that show the voltage with a resolution of 0.01 V and the current with a resolution of 0.001 A, so the values of voltage and current are monitored directly on the instrument during an experiment. Four control knobs are provided, two for coarse and fine adjustment of the voltage and two for coarse and fine adjustment of the current, together with built-in indicators of the operating mode of voltage or current stabilisation, a manual switch and a current-limiting function that switches the unit between the CV and CC modes automatically with indication. There are three output terminals, positive in red, negative in black and earth in green. A temperature-controlled fan switches on when the internal temperature exceeds 50 °C. The dimensions of the instrument are 260 × 125 × 145 mm, its weight is 2.3 kg, the operating temperature is from −10 to +40 °C and the relative humidity of the air is 80 %.
The set includes the power supply unit with the front panel and the digital displays — 1 pc, an AC power cord with a plug — 1 pc, a set of mounting brackets for installation on a rail — 1 pc, a set of contact terminals for connecting the load, red for the positive and black for the negative — 1 set, an earth terminal in green — 1 pc, replaceable fuses as a spare set — 2 pcs, the passport with the warranty coupon — 1 pc, a short version of the user instruction — 1 pc, and individual transport packaging — 1 pc. The unit is supplied ready for work and needs no assembly, and it is recommended to keep spare fuses and contact terminals in reserve.
The unit is installed on a table at the teacher’s workplace, on a horizontal stable surface in a well-ventilated place protected from vibration and moisture, with sufficient circulation of air around it, especially near the rear panel where the cooling radiator is located. The instrument is earthed through the third wire of the power cord, the power switch remains easily accessible, and before switching on the voltage and current knobs are set to the minimum position; after switching on the displays show 0 V and 0 A, the CV indicator lights up and the instrument is allowed to warm up for 5 minutes before the load is connected. The required voltage is set with the coarse and then the fine VOLTAGE knobs, and the maximum current permissible for the load is set with the CURRENT knobs; if the load exceeds the set current limit, the instrument passes automatically into the CC mode and returns to CV when the load decreases. Work is finished by returning the knobs to the minimum, disconnecting the load and switching the instrument off. The body and the front panel are wiped with a dry soft cloth, dust is removed from the ventilation openings with a brush or compressed air, and moisture is kept away from the displays and the ventilation openings. The instrument is not operated with visible damage to the body, the power cord or the terminals, is not immersed in liquid, and its terminals are not short-circuited without a current limit set. It is stored in a dry closed room at a temperature from +5 to +40 °C and relative humidity of 80 %. The product is not disposed of together with unsorted household waste, which is indicated by the crossed-out container marking on the product or its packaging. Marking and operating documentation are in Ukrainian, and the marking carries the trade mark, the model and a place for the inventory number. The service life is 5 years and the warranty period is 12 months from the date of sale.
