An electronic amplifier at the temperature of 1.4 K

The BF 245 transistors were investigated in the temperature range from300 K to 1.4 K. The transistors work satisfactorily in this temperature range. Some of the investigated transistors were used in a one-stage electronic amplifier. The amplifier operated properly in the whole temperature range between 300 K and 1.4 K . The voltage gain of the amplifier was 3 V/V in the temperature range from 4.2 K to 1.4 K. The dissipated power of the amplifier was 40 mW. Three thermal cycles 300 K … 1 . 4 K … 300 K were performed. The performance of the amplifier was not altered after the thermal cycles were completed.